Lactone-containing compound, polymer, resist composition, and patterning process

ABSTRACT

Lactone-containing compounds having formula (1) are novel wherein R 1  is H, F, methyl or trifluoromethyl, R 2  and R 3  are monovalent hydrocarbon groups, or R 2  and R 3  may together form an aliphatic hydrocarbon ring, R 4  is H or CO 2 R 5 , R 5  is a monovalent hydrocarbon group, W is CH 2 , O or S, and k 1  is 0 or 1. They are useful as monomers to produce polymers which are transparent to radiation≦500 nm. Radiation-sensitive resist compositions comprising the polymers as base resin exhibit excellent properties including resolution, pattern edge roughness, pattern density dependency and exposure margin.

CROSS-REFERENCE TO RELATED APPLICATION

This non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No. 2006-206233 filed in Japan on Jul. 28, 2006, the entire contents of which are hereby incorporated by reference.

TECHNICAL FIELD

This invention relates to (1) novel lactone-containing compounds useful as raw materials for the synthesis of functional materials, pharmaceutical and agricultural chemicals, (2) polymers comprising recurring units derived from the lactone-containing compounds, (3) resist compositions comprising the polymers, and (4) a patterning process using the resist compositions.

BACKGROUND ART

The recent drive for higher integration and operating speeds in LSI devices makes it necessary to further reduce the pattern rule. Deep-ultraviolet lithography was developed as an essential technology for micropatterning to a feature size of 0.3 μm or less. Among others, the KrF excimer laser lithography has been fully recognized as a commercial scale production technology.

With respect to chemically amplified resist compositions adapted for the photolithography using ArF excimer laser light of 193 nm wavelength as a light source, the primary requirement is, of course, a high transparency at that wavelength. They are also required to meet a high etch resistance sufficient to comply with film thickness reduction, a high sensitivity sufficient to minimize the burden to expensive optical materials, and among others, a high resolution sufficient to form an exact fine pattern. The key toward these requirements is to develop a base resin featuring high transparency, high rigidity and high reactivity. Active efforts have been devoted for such development.

Typical resins known to be highly transparent to ArF excimer laser light are copolymers of acrylic or methacrylic acid derivatives as disclosed in JP-A 4-39665.

One of the (meth)acrylic resins proposed thus far is a combination of (meth)acrylic units having methyladamantane ester as acid labile group units with (meth)acrylic units having lactone ring ester as adhesive group units as disclosed in JP-A 9-90637. Acid labile groups of exo form are described in U.S. Pat. No. 6,448,420 (JP-A 2000-327633). These groups have so high an acid elimination ability and require a low level of activation energy for acid elimination, affording a high resolution and low dependence on post-exposure bake (PEB). Norbornane lactone is also proposed as an adhesive group having enhanced etching resistance as disclosed in JP-A 2000-26446 and JP-A 2000-159758. These studies have achieved significant improvements in the resolution of ArF resists.

However, in an attempt to form a fine pattern having a pitch of less than 200 nm, prior art resist materials are difficult to form patterns and the patterns, if formed, have insufficient rectangularity and substantial roughness on their surface and sidewalls, and are hardly believed to clear the practically acceptable level. Of the problems associated with prior art resist materials, the most serious problem is the unevenness of fine line size, which is generally referred to as “line edge roughness” (LER). Since the LER has a substantial impact on the performance of semiconductor devices being fabricated, it is strongly desired to overcome this problem. If it is merely required to form a pattern in a smooth finish, that purpose may be attained to a more or less extent by selecting a resin with a lower molecular weight and/or a photoacid generator which generates a more mobile acid. With this approach, however, not only properties such as exposure dose dependency, pattern density dependency, and mask fidelity are extremely exacerbated, but also the line size itself rather becomes uneven because minute fluctuations at the mask are enlarged. This approach does not lead to a reduction of LER. Under the continuing demand for a further reduction of the pattern rule, the resist is required to provide good performance with respect to sensitivity, substrate adhesion and etch resistance and additionally, to find an essential solution to improve LER without sacrifice of resolution.

SUMMARY OF THE INVENTION

An object of the present invention is to provide lactone-containing compounds useful as monomers for the synthesis of polymers, polymers comprising recurring units derived from the lactone-containing compounds, and resist compositions comprising the polymers, the resist compositions exhibiting a high resolution and minimized pattern edge roughness when processed by photolithography using high-energy radiation such as ArF excimer laser radiation as a light source. Another object is to provide a patterning process using the resist compositions.

The inventor has found that a lactone-containing compound of the general formula (1) shown below can be readily prepared in high yields, and that a resist composition comprising a polymer derived from the lactone-containing compound as a base resin exhibits satisfactory properties including exposure dose dependency, pattern density dependency, and mask fidelity as well as minimized pattern edge roughness when processed by photolithography, so that the polymer is advantageously used in resist form for precise micropatterning.

Accordingly, the present invention provides a lactone-containing compound, polymer, resist composition, and patterning process, as defined below.

-   [1] A lactone-containing compound having the general formula (1).

Herein R¹ is hydrogen, fluorine, methyl or trifluoromethyl, R² and R³ are each independently a straight, branched or cyclic monovalent hydrocarbon group of 1 to 10 carbon atoms, or R² and R³ may bond together to form an aliphatic hydrocarbon ring with the carbon atom to which they are attached, R⁴ is hydrogen or CO₂R⁵, R⁵ is a straight, branched or cyclic monovalent hydrocarbon group of 1 to 15 carbon atoms which may have a halogen or oxygen atom, W is CH₂, O or S, with the proviso that R⁴ is CO₂R⁵ when W is CH₂, and R⁴ is hydrogen or CO₂R⁵ when W is O or S, and k¹ is 0 or 1.

-   [2] A polymer comprising recurring units derived from the     lactone-containing compound of [1]. -   [3] A polymer comprising recurring units having the general formula     (2).

Herein R¹ to R⁴, W, and k¹ are as defined above.

-   [4] The polymer of [2] or [3], further comprising recurring units     having at least one of the general formulas (3) to (6):

wherein R¹ is as defined above, R⁶ and R⁷ are each independently hydrogen or hydroxyl, X is an acid labile group, Y is a substituent group having a lactone structure different from formula (1), and Z is hydrogen, a fluoroalkyl group of 1 to 15 carbon atoms or a fluoroalcohol-containing substituent group of 1 to 15 carbon atoms.

-   [5] A resist composition comprising the polymer of any one of [2] to     [4] as a base resin. -   [6] A process for forming a pattern comprising the steps of applying     the resist composition of [5] onto a substrate to form a coating,     heat treating the coating, exposing the coating to high-energy     radiation or electron beam through a photomask, optionally heat     treating the exposed coating, and developing it with a developer.

It is noted that immersion lithography can be applied to the resist composition of the invention. The immersion lithography involves prebaking a resist film and exposing the resist film to light through a projection lens with a liquid medium interposed between the resist film and the projection lens. The ArF immersion lithography uses deionized water as the immersion medium. This technology, combined with a projection lens having a numerical aperture of at least 1.0, is important for the ArF lithography to survive to the 65 nm node, with a further development thereof being accelerated.

The resist composition of the invention allows the feature size of the pattern after development to be reduced by various shrinkage techniques. For example, the hole size can be shrunk by such known techniques as thermal flow, RELACS, SAFIRE, and WASOOM. More effective shrinkage of hole size by thermal flow is possible particularly when the inventive polymer is blended with a hydrogenated cycloolefin ring-opening metathesis polymer (ROMP) having a low Tg.

BENEFITS OF THE INVENTION

The lactone-containing compounds of the invention are useful as raw materials for the synthesis of functional materials, pharmaceutical and agricultural chemicals. They are most useful as monomers to produce polymers for the manufacture of radiation-sensitive resist compositions which have high transparency to radiation having a wavelength of up to 500 nm, especially up to 300 nm, and exhibit good development properties. Radiation-sensitive resist compositions comprising the polymers as base resin exhibit high resolution and are improved in pattern edge roughness, pattern density dependency and exposure margin when processed by photolithography. The polymers are advantageously used in resist form for precise micropatterning.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise.

The notation (Cn-Cm) means a group containing from n to m carbon atoms per group.

It is understood that for many structures represented by chemical formulae, there can exist enantiomers and diastereomers. Unless otherwise stated, a single formula collectively represents all such stereoisomers. The stereoisomers may be used alone or in admixture.

Lactone-Containing Compound

The lactone-containing compounds of the invention have the general formula (1).

Herein R¹ is a hydrogen atom, fluorine atom, methyl group or trifluoromethyl group. R² and R³ are each independently a straight, branched or cyclic monovalent hydrocarbon group of 1 to 10 carbon atoms, or R² and R³ may bond together to form an aliphatic hydrocarbon ring with the carbon atom to which they are attached. R⁴ is a hydrogen atom or CO₂R⁵ wherein R⁵ is a straight, branched or cyclic monovalent hydrocarbon group of 1 to 15 carbon atoms which may have one or more halogen or oxygen atoms. W is CH₂, O or S, with the proviso that R⁴ is CO₂R⁵ when W is CH₂, and R⁴ is hydrogen or CO₂R⁵ when W is O or S. The subscript k¹ is 0 or 1.

Examples of the straight, branched or cyclic monovalent C₁-C₁₀ hydrocarbon group represented by R² and R³ include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, cyclopentyl, cyclohexyl, 2-ethylhexyl, and n-octyl. R² and R³ may be the same or different. The aliphatic hydrocarbon rings that R² and R³ together form with the carbon atom to which they are attached are preferably those of 3 to 20 carbon atoms, more preferably 4 to 15 carbon atoms, and examples include cyclopropane, cyclobutane, cyclopentane, cyclohexane, bicyclo[2.2.1]heptane, bicyclo[2.2.2]octane, bicyclo[3.3.1]nonane, bicyclo[4.4.0]decane, and adamantane.

Examples of R⁵ include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, cyclopentyl, cyclohexyl, 1-methylcyclopentyl, 1-ethylcyclopentyl, 1-methylcyclohexyl, 1-ethylcyclohexyl, 2-ethylhexyl, n-octyl, 2-methyl-2-bicyclo[2.2.1]heptyl, 2-ethyl-2-bicyclo[2.2.1]heptyl, 2-methyl-2-adamantyl, 2-ethyl-2-adamantyl, 8-methyl-8-tricyclo[5.2.1.0^(2,6)]decyl, 8-ethyl-8-tricyclo[5.2.1.0^(2,6)]decyl, 3-methyl-3-tetracyclo[4.4.0.1^(2.5).1^(7,10)]dodecyl, 3-ethyl-3-tetracyclo[4.4.0.1^(2.5).1^(7,10)]dodecyl, methoxymethyl, ethoxymethyl, methoxyethyl, ethoxyethyl, and methoxyethoxyethyl, as well as the groups shown below.

It is noted that the broken line as depicted herein and throughout the specification denotes a valence bond.

Illustrative examples of the compound having formula (1) are given below wherein R¹ is as defined above.

The lactone-containing -compounds of formula (1) can be produced by the reaction schemes A and B shown below, for example, but the invention is not limited thereto.

Herein, R¹ to R⁴, W, and k¹ are as defined above. R⁸ is a hydrogen or halogen atom. R⁹ is a halogen atom, hydroxyl group or —OR¹¹. R¹⁰ is a halogen atom, hydroxyl group or —OR¹². R¹¹ is methyl, ethyl or a group of the formula:

R¹² is methyl, ethyl or a group of the formula:

M^(a) is Li, Na, K, Mg_(1/2), Ca_(1/2) or a substituted or unsubstituted ammonium. M^(b) is Li, Na, K, MgY^(a) or ZnY^(a) wherein Y^(a) is a halogen atom.

Preferably, the lactone-containing compounds of formula (1) wherein k¹ is equal to 0 are produced by scheme A including steps (i) and (ii), and the lactone-containing compounds of formula (1) wherein k¹ is equal to 1 are produced by scheme B including steps (iii) to (v), although the invention is not limited thereto.

More particularly, scheme A includes step (i) which is a reaction of a hydroxylactone compound (7) with an esterifying agent (8) into a (halo)acetic ester (9).

Notably, the synthesis of hydroxylactone compound (7) is described in JP-A 2000-159758 and U.S. Ser. No. 11/649,251 (Japanese Patent Application No. 2006-001102). For example, hydroxylactone compound (7) wherein R⁴ is CO₂R can be synthesized according to the following formula.

The reaction may be readily conducted by a well-known technique. The preferred esterifying agent (8) is an acid chloride (corresponding to formula (8) wherein R⁹ is chlorine) or a carboxylic acid (corresponding to formula (8) wherein R⁹ is hydroxyl). When an acid chloride is used as the esterifying agent, the reaction may be conducted in a solventless system or in a solvent such as methylene chloride, toluene, hexane, diethyl ether, tetrahydrofuran or acetonitrile, by sequentially or simultaneously adding hydroxylactone compound (7), a corresponding acid chloride such as 2-chloroacetic acid chloride or 2-bromoacetic acid chloride, and a base such as triethylamine, pyridine or 4-dimethylaminopyridine, and optionally cooling or heating. When a carboxylic acid is used as the esterifying agent, the reaction may be conducted in a solvent such as toluene or hexane, by heating hydroxylactone compound (7) and a corresponding carboxylic acid such as 2-chloroacetic acid or 2-bromoacetic acid, in the presence of an acid catalyst, and optionally removing the water formed during reaction from the system. Examples of the acid catalyst used herein include mineral acids such as hydrochloric acid, sulfuric acid, nitric acid and perchloric acid, and organic acids such as p-toluenesulfonic acid and benzenesulfonic acid.

Step (ii) is a reaction of a haloacetic ester (9) (formula (9) wherein R⁸ is a halogen atom) with a carboxylate salt (10) into a lactone-containing compound (1).

The reaction may be conducted by a standard technique. The carboxylic acid salt (10) used herein may be any of commercially available carboxylic acid salts such as metal salts of carboxylic acids, or may be prepared in a reaction system using a corresponding carboxylic acid such as methacrylic acid or acrylic acid and a base. The amount of carboxylic acid salt (10) used is preferably 0.5 to 10 moles, and more preferably 1.0 to 3.0 moles per mole of the reactant, (halo)acetic ester (9). With less than 0.5 mole of the carboxylic acid salt, a large proportion of the reactant may be left unreacted, leading to a substantial drop of yield. Using more than 10 moles of the carboxylic acid salt may be uneconomical because of an increased cost of the salt and decreased pot yields. When the carboxylic acid salt is prepared in a reaction system using a corresponding carboxylic acid and a base, the base used herein may be selected from among amines such as ammonia, triethylamine, pyridine, lutidine, collidine, and N,N-dimethylaniline; hydroxides such as sodium hydroxide, potassium hydroxide, and tetramethylammonium hydroxide; carbonates such as potassium carbonate and sodium hydrogen carbonate; metals such as sodium; metal hydrides such as sodium hydride; metal alkoxides such as sodium methoxide and potassium t-butoxide; organometallic compounds such as butyllithium and ethylmagnesium bromide; and metal amides such as lithium diisopropylamide, and mixtures thereof. The amount of the base used is preferably 0.2 to 10 moles, and more preferably 0.5 to 2.0 moles per mole of the carboxylic acid. With less than 0.2 mole of the base, a large proportion of the carboxylic acid may run to waste, leading to a cost deficiency. With more than 10 moles of the base, substantial side reactions may occur, resulting in a substantial drop of yield.

A solvent may be used in the reaction of step (ii). Suitable solvents include hydrocarbons such as toluene, xylene, hexane and heptane; chlorinated solvents such as methylene chloride, chloroform and dichloroethane; ethers such as diethyl ether, tetrahydrofuran and dibutyl ether; ketones such as acetone and 2-butanone; esters such as ethyl acetate and butyl acetate; nitrites such as acetonitrile; alcohols such as methanol and ethanol; aprotic polar solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide; and water, which may be used alone or in admixture. To the reaction system, a phase transfer catalyst such as tetrabutylammonium hydrogen sulfate may be added. An appropriate amount of the phase transfer catalyst added is 0.0001 to 1.0 mole, and more preferably 0.001 to 0.5 mole per mole of the reactant, (halo)acetic ester. Less than 0.0001 mole of the catalyst may exert little or no addition effect whereas more than 1.0 mole may be uneconomical because of an increased expense.

For the esterification reaction described above, the reaction temperature may be selected as appropriate in accordance with other reaction conditions and is preferably in the range from −70° C. to approximately the boiling point of the solvent, and more preferably in the range from 0° C. to approximately the boiling point of the solvent. The higher the reaction temperature, the more outstanding become side reactions. It is then important in attaining high yields that the reaction be carried out at as low a temperature as possible in the range for the reaction to proceed at a practically acceptable rate. Preferably the reaction time is determined so as to attain increased yields by monitoring the reaction process by thin-layer chromatography (TLC) or gas chromatography (GC). Usually, the reaction time is about 30 minutes to about 40 hours. From the reaction mixture, the lactone-containing compound (1) is recovered through an ordinary aqueous workup. If necessary, the compound may be purified by a standard technique such as distillation, recrystallization or chromatography.

Referring to scheme B, steps (iii) and (iv) are conversion of (halo)acetic ester (9) with the aid of a base into a metal enolate (11), and nucleophilic addition reaction of the enolate with a carbonyl compound (12) to form a β-hydroxyester compound (13).

Examples of the base which can be used in conjunction with the acetic ester of formula (9) wherein R⁸ is hydrogen include metal amides such as sodium amide, potassium amide, lithium diisopropylamide, potassium diisopropylamide, lithium dicyclohexylamide, potassium dicyclohexylamide, lithium 2,2,6,6-tetramethylpiperidine, lithium bistrimethylsilylamide, sodium bistrimethylsilylamide, potassium bistrimethylsilylamide, lithium isopropylcyclohexylamide, and bromo-magnesium diisopropylamide; alkoxides such as sodium methoxide, sodium ethoxide, lithium methoxide, lithium ethoxide, lithium tert-butoxide, and potassium tert-butoxide; inorganic hydroxides such as sodium hydroxide, lithium hydroxide, potassium hydroxide, barium hydroxide, and tetra-n-butylammonium hydroxide; inorganic carbonates such as sodium carbonate, sodium hydrogen carbonate, lithium carbonate, and potassium carbonate; metal hydrides such as borane, alkylboranes, sodium hydride, lithium hydride, potassium hydride, and calcium hydride; and alkyl metal compounds such as trityllithium, tritylsodium, tritylpotassium, methyllithium, phenyllithium, sec-butyllithium, tert-butyllithium, and ethylmagnesium bromide. Examples of the base which can be used in conjunction with the haloacetic ester of formula (9) wherein R⁸ is halogen include, but are not limited to, metals such as lithium, sodium, potassium, magnesium, and zinc (e.g., a reaction using haloacetic ester and zinc is known as Reformatsky reaction).

In the addition reaction of metal enolate (11) with carbonyl compound (12), it is preferable to use 0.8 to 1.5 moles of the metal enolate per mole of the carbonyl compound. Examples of the solvent used herein include ethers such as tetrahydrofuran, diethyl ether, di-n-butyl ether, 1,4-dioxane, ethylene glycol dimethyl ether, and ethylene glycol diethyl ether, and hydrocarbons such as hexane, heptane, benzene, toluene, xylene, and cumene, which may be used alone or in admixture. The reaction temperature and time vary with the identity of reactants used. For example, where a metal enolate is formed using as the reactants an acetic ester of formula (9) wherein R⁸ is hydrogen and a strong base such as lithium diisopropylamide or lithium bistrimethylsilylamide, the resulting metal enolate is thermally unstable, and it is then preferred that the reaction temperature of step (iv) be kept as low as −80° C. to −30° C. and the reaction time be about 0.5 to 3 hours. In another example where a metal enolate is formed using a haloacetic ester of formula (9) wherein R⁸ is halogen and a metal such as zinc or magnesium, it is preferred that the reaction temperature of step (iv) be kept at 20° C. to 80° C. and the reaction time be about 1 to 20 hours. However, the reaction conditions are not limited thereto.

Step (v) is a reaction of the β-hydroxyester compound (13) with an esterifying agent (14) into a lactone-containing compound (1).

The reaction may be readily conducted by a well-known technique. The preferred esterifying agent (14) is an acid chloride (corresponding to formula (14) wherein R¹⁰ is chlorine) or a carboxylic acid (corresponding to formula (14) wherein R¹⁰ is hydroxyl). When an acid chloride is used as the esterifying agent, the reaction may be conducted in a solventless system or in a solvent such as methylene chloride, toluene or hexane, by sequentially or simultaneously adding β-hydroxyl ester compound (13), a corresponding acid chloride such as methacrylic acid chloride or acrylic acid chloride, and a base such as triethylamine, pyridine or 4-dimethylaminopyridine, and optionally cooling or heating. When a carboxylic acid is used as the esterifying agent, the reaction may be conducted in a solvent such as toluene or hexane, by heating β-hydroxy ester compound (13) and a corresponding carboxylic acid such as methacrylic acid or acrylic acid, in the presence of an acid catalyst, and optionally removing the water formed during reaction from the system. Examples of the acid catalyst used herein include mineral acids such as hydrochloric acid, sulfuric acid, nitric acid and perchloric acid, and organic acids such as p-toluenesulfonic acid and benzenesulfonic acid.

Polymer

In the second aspect, the invention provides a polymer comprising recurring units derived from the lactone-containing compound of formula (1).

Specifically, the recurring units derived from the lactone-containing compound of formula (1) include recurring units having the general formula (2).

Herein R¹ to R⁴, W and k¹ are as defined above.

In addition to the recurring units derived from the compounds having formula (1), specifically recurring units having formula (2), the polymers of the invention may further comprise recurring units having at least one of the general formulas (3) to (6).

Herein R¹ is as defined above, R⁶ and R⁷ are each independently a hydrogen atom or hydroxyl group, X is an acid labile group, Y is a substituent group having a lactone structure different from formula (1), and Z is a hydrogen atom, a fluoroalkyl group of 1 to 15 carbon atoms or a fluoroalcohol-containing substituent group of 1 to 15 carbon atoms.

Under the action of acid, a polymer comprising recurring units of formula (3) is decomposed to generate carboxylic acid, turning to be an alkali soluble polymer. The acid labile group represented by X may be selected from a variety of such groups. Examples of the acid labile group are groups of the following general formulae (L1) to (L4), tertiary alkyl groups of 4 to 20 carbon atoms, preferably 4 to 15 carbon atoms, trialkylsilyl groups in which each alkyl moiety has 1 to 6 carbon atoms, and oxoalkyl groups of 4 to 20 carbon atoms.

In these formulae, the broken line denotes a valence bond. R^(L01) and R^(L02) are hydrogen or straight, branched or cyclic alkyl groups of 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms. Exemplary alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, cyclopentyl, cyclohexyl, 2-ethylhexyl, n-octyl, norbornyl, tricyclodecanyl, tetracyclododecanyl, and adamantyl. R^(L03) is a monovalent hydrocarbon group of 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms, which may contain a hetero atom such as oxygen, examples of which include unsubstituted straight, branched or cyclic alkyl groups and substituted forms of such alkyl groups in which some hydrogen atoms are replaced by hydroxyl, alkoxy, oxo, amino, alkylamino or the like. Illustrative examples of the substituted alkyl groups are shown below.

A pair of R^(L01) and R^(L02), R^(L01) and R^(L03), or R^(L02) and R^(L03) may form a ring with carbon and oxygen atoms to which they are attached. Each of R^(L01), R^(L02) and R^(L03) is a straight or branched alkylene group of 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms when they form a ring.

R^(L04) is a tertiary alkyl group of 4 to 20 carbon atoms, preferably 4 to 15 carbon atoms, a trialkylsilyl group in which each alkyl moiety has 1 to 6 carbon atoms, an oxoalkyl group of 4 to 20 carbon atoms, or a group of formula (L1). Exemplary tertiary alkyl groups are tert-butyl, tert-amyl, 1,1-diethylpropyl, 2-cyclopentylpropan-2-yl, 2-cyclohexylpropan-2-yl, 2-(bicyclo[2.2.1]heptan-2-yl)propan-2-yl, 2-(adamantan-1-yl)propan-2-yl, 1-ethylcyclopentyl, 1-butylcyclopentyl, 1-ethylcyclohexyl, 1-butylcyclohexyl, 1-ethyl-2-cyclopentenyl, 1-ethyl-2-cyclohexenyl, 2-methyl-2-adamantyl, and 2-ethyl-2-adamantyl. Exemplary trialkylsilyl groups are trimethylsilyl, triethylsilyl, and dimethyl-tert-butylsilyl. Exemplary oxoalkyl groups are 3-oxocyclohexyl, 4-methyl-2-oxooxan-4-yl, and 5-methyl-2-oxooxolan-5-yl. Letter y is an integer of 0 to 6.

In formula (L3), R^(L05) is a substituted or unsubstituted, straight, branched or cyclic alkyl group of 1 to 8 carbon atoms or a substituted or unsubstituted aryl group of 6 to 20 carbon atoms. Examples of the optionally substituted alkyl group include straight, branched or cyclic alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, tert-amyl, n-pentyl, n-hexyl, cyclopentyl, and cyclohexyl, and substituted forms of such groups in which some hydrogen atoms are substituted with hydroxyl, alkoxy, carboxy, alkoxycarbonyl, oxo, amino, alkylamino, cyano, mercapto, alkylthio, sulfo or other groups. Examples of the optionally substituted aryl groups include phenyl, methylphenyl, naphthyl, anthryl, phenanthryl, and pyrenyl. Letter m is equal to 0 or 1, n is equal to 0, 1, 2 or 3, and 2m+n is equal to 2 or 3.

In formula (L4), R^(L06) is a substituted or unsubstituted, straight, branched or cyclic alkyl group of 1 to 8 carbon atoms or a substituted or unsubstituted aryl group of 6 to 20 carbon atoms. Examples of these groups are the same as exemplified for R^(L05). R^(L07) to R^(L16) independently represent hydrogen or monovalent hydrocarbon groups of 1 to 15 carbon atoms. Exemplary hydrocarbon groups are straight, branched or cyclic alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, tert-amyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl and cyclohexylbutyl, and substituted forms of these groups in which some hydrogen atoms are replaced by hydroxyl, alkoxy, carboxy, alkoxycarbonyl, oxo, amino, alkylamino, cyano, mercapto, alkylthio, sulfo or other groups. Alternatively, R^(L07) to R^(L16), taken together, form a ring (for example, a pair of R^(L07) and R^(L08), R^(L07) and R^(L09), R^(L08) and R^(L10), R^(L09) and R^(L10), R^(L11) and R^(L12), R^(L13) and R^(L14), or a similar pair form a ring). Each of R^(L07) to R^(L16) represents a divalent C₁-C₁₅ hydrocarbon group when they form a ring, examples of which are the ones exemplified above for the monovalent hydrocarbon groups, with one hydrogen atom being eliminated. Two of R^(L07) to R^(L16) which are attached to vicinal carbon atoms (for example, a pair of R^(L07) and R^(L09) R^(L09) and R^(L15), R^(L13) and R^(L15), or a similar pair) may bond together directly to form a double bond.

Of the acid labile groups of formula (L1), the straight and branched ones are exemplified by the following groups.

Of the acid labile groups of formula (L1), the cyclic ones are, for example, tetrahydrofuran-2-yl, 2-methyltetrahydrofuran-2-yl, tetrahydropyran-2-yl, and 2-methyltetrahydropyran-2-yl.

Examples of the acid labile groups of formula (L2) include tert-butoxycarbonyl, tert-butoxycarbonylmethyl, tert-amyloxycarbonyl, tert-amyloxycarbonylmethyl, 1,1-diethylpropyloxycarbonyl, 1,1-diethylpropyloxycarbonylmethyl, 1-ethylcyclopentyloxycarbonyl, 1-ethylcyclopentyloxycarbonylmethyl, 1-ethyl-2-cyclopentenyloxycarbonyl, 1-ethyl-2-cyclopentenyloxycarbonylmethyl, 1-ethoxyethoxycarbonylmethyl, 2-tetrahydropyranyloxycarbonylmethyl, and 2-tetrahydrofuranyloxycarbonylmethyl groups.

Examples of the acid labile groups of formula (L3) include 1-methylcyclopentyl, 1-ethylcyclopentyl, 1-n-propylcyclopentyl, 1-isopropylcyclopentyl, 1-n-butylcyclopentyl, 1-sec-butylcyclopentyl, 1-cyclohexylcyclopentyl, 1-(4-methoxy-n-butyl)cyclopentyl, 1-methylcyclohexyl, 1-ethylcyclohexyl, 3-methyl-1-cyclopenten-3-yl, 3-ethyl-1-cyclopenten-3-yl, 3-methyl-1-cyclohexen-3-yl, and 3-ethyl-1-cyclohexen-3-yl groups.

Of the acid labile groups having formula (L4), groups having the following formulas (L4-1) to (L4-4) are preferred.

In formulas (L4-1) to (L4-4), the broken line denotes a bonding site and direction. R^(L41) is each independently a monovalent hydrocarbon group, typically a straight, branched or cyclic alkyl group of 1 to 10 carbon atoms, such as methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, tert-amyl, n-pentyl, n-hexyl, cyclopentyl and cyclohexyl.

For formulas (L4-1) to (L4-4), there can exist enantiomers and diastereomers. Each of formulae (L4-1) to (L4-4) collectively represents all such stereoisomers. Such stereoisomers may be used alone or in admixture.

For example, the general formula (L4-3) represents one or a mixture of two selected from groups having the following general formulas (L4-3-1) and (L4-3-2).

Similarly, the general formula (L4-4) represents one or a mixture of two or more selected from groups having the following general formulas (L4-4-1) to (L4-4-4).

Each of formulas (L4-1) to (L4-4), (L4-3-1) and (L4-3-2), and (L4-4-1) to (L4-4-4) collectively represents an enantiomer thereof and a mixture of enantiomers.

It is noted that in the above formulas (L4-1) to (L4-4), (L4-3-1) and (L4-3-2), and (L4-4-1) to (L4-4-4), the bond direction is on the exo side relative to the bicyclo[2.2.1]heptane ring, which ensures high reactivity for acid catalyzed elimination reaction (see JP-A 2000-336121). In preparing these monomers having a tertiary exo-alkyl group of bicyclo[2.2.1]heptane skeleton as a substituent group, there may be contained monomers substituted with an endo-alkyl group as represented by the following formulas (L4-1-endo) to (L4-4-endo). For good reactivity, an exo proportion of at least 50% is preferred, with an exo proportion of at least 80% being more preferred.

See JP-A 2000-336121.

Illustrative examples of the acid labile group of formula (L4) are given below.

Examples of the tertiary alkyl groups of 4 to 20 carbon atoms, trialkylsilyl groups in which each alkyl moiety has 1 to 6 carbon atoms, and oxoalkyl groups of 4 to 20 carbon atoms are as exemplified for R^(L04).

Illustrative examples of the recurring units of formula (3) are given below although the invention is not limited thereto.

Illustrative examples of the recurring units of formula (4) are given below although the invention is not limited thereto.

Illustrative examples of the recurring units of formula (5) are given below although the invention is not limited thereto.

Illustrative examples of the recurring units of formula (6) are given below although the invention is not limited thereto.

In addition to the foregoing units, the polymers of the invention may further comprise recurring units derived from carbon-to-carbon double bond-bearing monomers other than the above-described ones, for example, substituted acrylic acid esters such as methyl methacrylate, methyl chrotonate, dimethyl maleate and dimethyl itaconate, unsaturated carboxylic acids such as maleic acid, fumaric acid, and itaconic acid, cyclic olefins such as norbornene, norbornene derivatives, and tetracyclo[4.4.0.1^(2,5).17^(7,10)]dodecene derivatives, unsaturated acid anhydrides such as itaconic anhydride, and other monomers.

The polymers of the invention generally have a weight average molecular weight (Mw) of 1,000 to 500,000, and preferably 3,000 to 100,000, as measured by gel permeation chromatography (GPC) using polystyrene standards. Outside the range, there may result an extreme drop of etch resistance, and a drop of resolution due to difficulty to gain a dissolution rate difference before and after exposure.

In the inventive polymers, appropriate proportions of the respective recurring units derived from the monomers are given below although the invention is not limited thereto.

The inventive polymers may contain:

-   (I) constituent units of one or more types having formula (2)     derived from monomers of formula (1) in a proportion of more than 0     mol % to 100 mol %, preferably 5 to 70 mol %, and more preferably 10     to 50 mol %, -   (II) constituent units of one or more types having formulas (3)     to (6) in a proportion of 0 mol % to less than 100 mol %, preferably     1 to 95 mol %, and more preferably 20 to 90 mol %, and -   (III) constituent units of one or more types derived from other     monomers in a proportion of 0 to 80 mol %, preferably 0 to 70 mol %,     and more preferably 0 to 50 mol %, based on the total moles of     constituent units.

The polymers of the invention are prepared by copolymerization reaction using the compound of formula (1) as a first monomer and polymerizable double bond-bearing compounds as second and subsequent monomers. The copolymerization reaction to produce the inventive polymers may be performed in various modes, preferably radical polymerization, anionic polymerization or coordination polymerization.

For radical polymerization, preferred reaction conditions include (a) a solvent selected from among hydrocarbons such as benzene, ethers such as tetrahydrofuran, alcohols such as ethanol, and ketones such as methyl isobutyl ketone, (b) a polymerization initiator selected from azo compounds such as 2,2′-azobisisobutyronitrile and peroxides such as benzoyl peroxide and lauroyl peroxide, (c) a temperature of about 0° C. to about 100° C., and (d) a time of about ½ hour to about 48 hours. Reaction conditions outside the described range may be employed if desired.

For anionic polymerization, preferred reaction conditions include (a) a solvent selected from among hydrocarbons such as benzene, ethers such as tetrahydrofuran, and liquid ammonia, (b) a polymerization initiator selected from metals such as sodium and potassium, alkyl metals such as n-butyllithium and sec-butyllithium, ketyl, and Grignard reagents, (c) a temperature of about −78° C. to about 0° C., (d) a time of about ½ hour to about 48 hours, and (e) a stopper selected from among proton-donative compounds such as methanol, halides such as methyl iodide, and electrophilic compounds. Reaction conditions outside the described range may be employed if desired.

For coordination polymerization, preferred reaction conditions include (a) a solvent selected from among hydrocarbons such as n-heptane and toluene, (b) a catalyst selected from Ziegler-Natta catalysts comprising a transition metal (e.g., titanium) and alkylaluminum, Phillips catalysts of metal oxides having chromium or nickel compounds carried thereon, and olefin-metathesis mixed catalysts as typified by tungsten and rhenium mixed catalysts, (c) a temperature of about 0° C. to about 100° C., and (d) a time of about ½ hour to about 48 hours. Reaction conditions outside the described range may be employed if desired.

Resist Composition

Since the polymer of the invention is useful as the base resin of a resist composition, the other aspect of the invention provides a resist composition comprising the polymer and specifically a chemically amplified positive resist composition comprising the polymer. Typically, the resist composition contains (A) the inventive polymer as a base resin, (B) an acid generator, (C) an organic solvent, and optionally (D) a quencher and (E) a surfactant.

In addition to the inventive polymer, the base resin (A) may include another polymer having a dissolution rate in alkaline developer that increases under the action of acid, if necessary. Examples of the other polymer include, but are not limited to, (i) poly(meth)acrylic acid derivatives, (ii) norbornene derivative-maleic anhydride copolymers, (iii) hydrogenated products of ring-opening metathesis polymers (ROMP), and (iv) vinyl ether-maleic anhydride-(meth)acrylic acid derivative copolymers.

Of these, the hydrogenated products of ring-opening metathesis polymers are synthesized by the method illustrated in JP-A 2003-66612. Illustrative examples of such hydrogenated polymers include those polymers having the recurring units shown below, but are not limited thereto.

The inventive polymer and the other polymer are preferably blended in a weight ratio from 100:0 to 10:90, more preferably from 100:0 to 20:80. If the blend ratio of the inventive polymer is below this range, the resist composition would become poor in some of the desired properties. The properties of the resist composition can be adjusted by properly changing the blend ratio of the inventive polymer.

The other polymer is not limited to one type and a mixture of two or more other polymers may be added. The use of plural polymers allows for easy adjustment of resist properties.

Photoacid Generator

As the acid generator (B), a photoacid generator is typically used. It is any compound capable of generating an acid upon exposure to high-energy radiation. Suitable photoacid generators include sulfonium salts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxyimide, and oxime-O-sulfonate acid generators. Exemplary acid generators are given below while they may be used alone or in admixture of two or more.

Sulfonium salts are salts of sulfonium cations with sulfonates, bis(substituted alkylsulfonyl)imides and tris(substituted alkylsulfonyl)methides. Exemplary sulfonium cations include triphenylsulfonium, (4-tert-butoxyphenyl)diphenylsulfonium, bis(4-tert-butoxyphenyl)phenylsulfonium, tris(4-tert-butoxyphenyl)sulfonium, (3-tert-butoxyphenyl)diphenylsulfonium, bis(3-tert-butoxyphenyl)phenylsulfonium, tris(3-tert-butoxyphenyl)sulfonium, (3,4-di-tert-butoxyphenyl)diphenylsulfonium, bis(3,4-di-tert-butoxyphenyl)phenylsulfonium, tris(3,4-di-tert-butoxyphenyl)sulfonium, diphenyl(4-thiophenoxyphenyl)sulfonium, (4-tert-butoxycarbonylmethyloxyphenyl)diphenylsulfonium, tris(4-tert-butoxycarbonylmethyloxyphenyl)sulfonium, (4-tert-butoxyphenyl)bis(4-dimethylaminophenyl)sulfonium, tris(4-dimethylaminophenyl)sulfonium, 4-methylphenyldiphenylsulfonium, 4-tert-butylphenyldiphenylsulfonium, bis(4-methylphenyl)phenylsulfonium, bis(4-tert-butylphenyl)phenylsulfonium, tris(4-methylphenyl)sulfonium, tris(4-tert-butylphenyl)sulfonium, tris(phenylmethyl)sulfonium, 2-naphthyldiphenylsulfonium, dimethyl(2-naphthyl)sulfonium, 4-hydroxyphenyldimethylsulfonium, 4-methoxyphenyldimethylsulfonium, trimethylsulfonium, 2-oxocyclohexylcyclohexylmethylsulfonium, trinaphthylsulfonium, tribenzylsulfonium, diphenylmethylsulfonium, dimethylphenylsulfonium, 2-oxopropylthiacyclopentanium, 2-oxobutylthiacyclopentanium, 2-oxo-3,3-dimethylbutylthiacyclopentanium, 2-oxo-2-phenylethylthiacyclopentanium, 4-n-butoxynaphthyl-1-thiacyclopentanium, and 2-n-butoxynaphthyl-1-thiacyclopentanium. Exemplary sulfonates include trifluoromethanesulfonate, pentafluoroethanesulfonate, heptafluoropropanesulfonate, nonafluorobutanesulfonate, tridecafluorohexanesulfonate, perfluoro(4-ethylcyclohexane)sulfonate, heptadecafluorooctanesulfonate, 2,2,2-trifluoroethanesulfonate, pentafluorobenzenesulfonate, 4-(trifluoromethyl)benzenesulfonate, 4-fluorobenzenesulfonate, mesitylenesulfonate, 2,4,6-triisopropylbenzenesulfonate, toluenesulfonate, benzenesulfonate, 4-(p-toluenesulfonyloxy)benzenesulfonate, 6-(p-toluenesulfonyloxy)naphthalene-2-sulfonate, 4-(p-toluenesulfonyloxy)naphthalene-1-sulfonate, 5-(p-toluenesulfonyloxy)naphthalene-1-sulfonate, 8-(p-toluenesulfonyloxy)naphthalene-1-sulfonate, naphthalenesulfonate, camphorsulfonate, octanesulfonate, dodecylbenzenesulfonate, butanesulfonate, methanesulfonate, 1,1-difluoro-2-naphthyl-ethanesulfonate, 1,1,2,2-tetrafluoro-2-(norbornan-2-yl)ethanesulfonate, 1,1,2,2-tetrafluoro-2-(tetracyclo[4.4.0.1^(2,5).1^(7,10)]dodec-3-en-8-yl)ethanesulfonate, 2-benzoyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 1,1,3,3,3-pentafluoro-2-(4-phenylbenzoyloxy)propanesulfonate, 1,1,3,3,3-pentafluoro-2-pivaloyloxypropanesulfonate, 2-cyclohexanecarbonyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 1,1,3,3,3-pentafluoro-2-furoyloxypropanesulfonate, 2-naphthoyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 2-(4-tert-butylbenzoyloxy)-1,1,3,3,3-pentafluoropropane-sulfonate, 2-(1-adamantanecarbonyloxy)-1,1,3,3,3-pentafluoropropane-sulfonate, 2-acetyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 1,1,3,3,3-pentafluoro-2-hydroxypropanesulfonate, 1,1,3,3,3-pentafluoro-2-tosyloxypropanesulfonate, 1,1-difluoro-2-tosyloxyethanesulfonate, adamantanemethoxycarbonyldifluoromethanesulfonate, 1-(3-hydroxymethyladamantane)methoxycarbonyldifluoromethanesulfonate, methoxycarbonyldifluoromethanesulfonate, 1-(hexahydro-2-oxo-3,5-methano-2H-cyclopenta[b]furan-6-yloxy-carbonyl)difluoromethanesulfonate, and 4-oxo-1-adamantyloxycarbonyldifluoromethanesulfonate. Exemplary bis(substituted alkylsulfonyl)imides include bis(trifluoromethylsulfonyl)imide, bis(pentafluoroethylsulfonyl)imide, bis(heptafluoropropylsulfonyl)imide, and perfluoro(1,3-propylenebissulfonyl)imide. A typical tris(substituted alkylsulfonyl)methide is tris(trifluoromethylsulfonyl)methide. Sulfonium salts based on combination of the foregoing-examples are included.

Iodonium salts are salts of iodonium cations with sulfonates, bis(substituted alkylsulfonyl)imides and tris(substituted alkylsulfonyl)methides. Exemplary iodonium cations are aryliodonium cations including diphenyliodinium, bis(4-tert-butylphenyl)iodonium, 4-tert-butoxyphenylphenyliodonium, and 4-methoxyphenylphenyliodonium. Exemplary sulfonates include trifluoromethanesulfonate, pentafluoroethanesulfonate, heptafluoropropanesulfonate, nonafluorobutanesulfonate, tridecafluorohexanesulfonate, perfluoro(4-ethylcyclohexane)sulfonate, heptadecafluorooctanesulfonate, 2,2,2-trifluoroethanesulfonate, pentafluorobenzenesulfonate, 4-(trifluoromethyl)benzenesulfonate, 4-fluorobenzenesulfonate, mesitylenesulfonate, 2,4,6-triisopropylbenzenesulfonate, toluenesulfonate, benzenesulfonate, 4-(p-toluenesulfonyloxy)benzenesulfonate, 6-(p-toluenesulfonyloxy)naphthalene-2-sulfonate, 4-(p-toluenesulfonyloxy)naphthalene-1-sulfonate, 5-(p-toluenesulfonyloxy)naphthalene-1-sulfonate, 8-(p-toluenesulfonyloxy)naphthalene-1-sulfonate, naphthalenesulfonate, camphorsulfonate, octanesulfonate, dodecylbenzenesulfonate, butanesulfonate, methanesulfonate, 1,1-difluoro-2-naphthyl-ethanesulfonate, 1,1,2,2-tetrafluoro-2-(norbornan-2-yl)ethanesulfonate, 1,1,2,2-tetrafluoro-2-(tetracyclo[4.4.0.1^(2,5).1^(7,10)]dodec-3-en-8-yl)ethanesulfonate, 2-benzoyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 1,1,3,3,3-pentafluoro-2-(4-phenylbenzoyloxy)propanesulfonate, 1,1,3,3,3-pentafluoro-2-pivaloyloxypropanesulfonate, 2-cyclohexanecarbonyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 1,1,3,3,3-pentafluoro-2-furoyloxypropanesulfonate, 2-naphthoyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 2-(4-tert-butylbenzoyloxy)-1,1,3,3,3-pentafluoropropane-sulfonate, 2-(1-adamantanecarbonyloxy)-1,1,3,3,3-pentafluoropropane-sulfonate, 2-acetyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 1,1,3,3,3-pentafluoro-2-hydroxypropanesulfonate, 1,1,3,3,3-pentafluoro-2-tosyloxypropanesulfonate, 1,1-difluoro-2-tosyloxyethanesulfonate, adamantanemethoxycarbonyldifluoromethanesulfonate, 1-(3-hydroxymethyladamantane)methoxycarbonyldifluoromethane-sulfonate, methoxycarbonyldifluoromethanesulfonate, 1-(hexahydro-2-oxo-3,5-methano-2H-cyclopenta[b]furan-6-yloxy-carbonyl)difluoromethanesulfonate, and 4-oxo-1-adamantyloxycarbonyldifluoromethanesulfonate. Exemplary bis(substituted alkylsulfonyl)imides include bis(trifluoromethylsulfonyl)imide, bis(pentafluoroethylsulfonyl)imide, bis(heptafluoropropylsulfonyl)imide, and perfluoro(1,3-propylenebissulfonyl)imide. A typical tris(substituted alkylsulfonyl)methide is tris(trifluoromethylsulfonyl)methide. Iodonium salts based on combination of the foregoing examples are included.

Exemplary sulfonyldiazomethane compounds include bissulfonyldiazomethane compounds and sulfonyl-carbonyldiazomethane compounds such as bis(ethylsulfonyl)diazomethane, bis(1-methylpropylsulfonyl)diazomethane, bis(2-methylpropylsulfonyl)diazomethane, bis(1,1-dimethylethylsulfonyl)diazomethane, bis(cyclohexylsulfonyl)diazomethane, bis(perfluoroisopropylsulfonyl)diazomethane, bis(phenylsulfonyl)diazomethane, bis(4-methylphenylsulfonyl)diazomethane, bis(2,4-dimethylphenylsulfonyl)diazomethane, bis(4-acetyloxyphenylsulfonyl)diazomethane, bis(4-(methanesulfonyloxy)phenylsulfonyl)diazomethane, bis(4-(p-toluenesulfonyloxy)phenylsulfonyl)diazomethane, bis(4-n-hexyloxyphenylsulfonyl)diazomethane, bis(2-methyl-4-n-hexyloxyphenylsulfonyl)diazomethane, bis(2,5-dimethyl-4-n-hexyloxyphenylsulfonyl)diazomethane, bis(3,5-dimethyl-4-n-hexyloxyphenylsulfonyl)diazomethane, bis(2-methyl-5-isopropyl-4-n-hexyloxyphenylsulfonyl)-diazomethane, bis(2-naphthylsulfonyl)diazomethane, 4-methylphenylsulfonylbenzoyldiazomethane, tert-butylcarbonyl-4-methylphenylsulfonyldiazomethane, 2-naphthylsulfonylbenzoyldiazomethane, 4-methylphenylsulfonyl-2-naphthoyldiazomethane, methylsulfonylbenzoyldiazomethane, and tert-butoxycarbonyl-4-methylphenylsulfonyldiazomethane.

N-sulfonyloxydicarboxyimide photoacid generators include combinations of imide skeletons with sulfonates. Exemplary imide skeletons are succinimide, naphthalenedicarboxyimide, phthalimide, cyclohexyldicarboxyimide, 5-norbornene-2,3-dicarboxyimide, and 7-oxabicyclo[2.2.1]-5-heptene-2,3-dicarboxyimide. Exemplary sulfonates include trifluoromethanesulfonate, pentafluoroethanesulfonate, heptafluoropropanesulfonate, nonafluorobutanesulfonate, tridecafluorohexanesulfonate, perfluoro(4-ethylcyclohexane)sulfonate, heptadecafluorooctanesulfonate, 2,2,2-trifluoroethanesulfonate, pentafluorobenzenesulfonate, 4-(trifluoromethyl)benzenesulfonate, 4-fluorobenzenesulfonate, mesitylenesulfonate, 2,4,6-triisopropylbenzenesulfonate, toluenesulfonate, benzenesulfonate, 4-(p-toluenesulfonyloxy)benzenesulfonate, 6-(p-toluenesulfonyloxy)naphthalene-2-sulfonate, 4-(p-toluenesulfonyloxy)naphthalene-1-sulfonate, 5-(p-toluenesulfonyloxy)naphthalene-1-sulfonate, 8-(p-toluenesulfonyloxy)naphthalene-1-sulfonate, naphthalenesulfonate, camphorsulfonate, octanesulfonate, dodecylbenzenesulfonate, butanesulfonate, methanesulfonate, 1,1-difluoro-2-naphthyl-ethanesulfonate, 1,1,2,2-tetrafluoro-2-(norbornan-2-yl)ethanesulfonate, 1,1,2,2-tetrafluoro-2-(tetracyclo[4.4.0.1^(2,5).1^(7,10)]dodec-3-en-8-yl)ethanesulfonate, 2-benzoyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 1,1,3,3,3-pentafluoro-2-(4-phenylbenzoyloxy)propanesulfonate, 1,1,3,3,3-pentafluoro-2-pivaloyloxypropanesulfonate, 2-cyclohexanecarbonyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 1,1,3,3,3-pentafluoro-2-furoyloxypropanesulfonate, 2-naphthoyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 2-(4-tert-butylbenzoyloxy)-1,1,3,3,3-pentafluoropropane-sulfonate, 2-(1-adamantanecarbonyloxy)-1,1,3,3,3-pentafluoropropane-sulfonate, 2-acetyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 1,1,3,3,3-pentafluoro-2-hydroxypropanesulfonate, 1,1,3,3,3-pentafluoro-2-tosyloxypropanesulfonate, 1,1-difluoro-2-tosyloxyethanesulfonate, adamantanemethoxycarbonyldifluoromethanesulfonate, 1-(3-hydroxymethyladamantane)methoxycarbonyldifluoromethane-sulfonate, methoxycarbonyldifluoromethanesulfonate, 1-(hexahydro-2-oxo-3,5-methano-2H-cyclopenta[b]furan-6-yl-oxycarbonyl)difluoromethanesulfonate, and 4-oxo-1-adamantyloxycarbonyldifluoromethanesulfonate.

Benzoinsulfonate photoacid generators include benzoin tosylate, benzoin mesylate, and benzoin butanesulfonate.

Pyrogallol trisulfonate photoacid generators include pyrogallol, phloroglucin, catechol, resorcinol, hydroquinone, in which all the hydroxyl groups are substituted by trifluoromethanesulfonate, pentafluoroethanesulfonate, heptafluoropropanesulfonate, nonafluorobutanesulfonate, tridecafluorohexanesulfonate, perfluoro(4-ethylcyclohexane)sulfonate, heptadecafluorooctanesulfonate, 2,2,2-trifluoroethanesulfonate, pentafluorobenzenesulfonate, 4-(trifluoromethyl)benzenesulfonate, 4-fluorobenzenesulfonate, mesitylenesulfonate, 2,4,6-triisopropylbenzenesulfonate, toluenesulfonate, benzenesulfonate, 4-(p-toluenesulfonyloxy)benzenesulfonate, 6-(p-toluenesulfonyloxy)naphthalene-2-sulfonate, 4-(p-toluenesulfonyloxy)naphthalene-1-sulfonate, 5-(p-toluenesulfonyloxy)naphthalene-1-sulfonate, 8-(p-toluenesulfonyloxy)naphthalene-1-sulfonate, naphthalenesulfonate, camphorsulfonate, octanesulfonate, dodecylbenzenesulfonate, butanesulfonate, methanesulfonate, 1,1-difluoro-2-naphthylethanesulfonate, 1,1,2,2-tetrafluoro-2-(norbornan-2-yl)ethanesulfonate, 1,1,2,2-tetrafluoro-2-(tetracyclo[4.4.0.1^(2,5).1^(7,10)]dodec-3-en-8-yl)ethanesulfonate, 2-benzoyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 1,1,3,3,3-pentafluoro-2-(4-phenylbenzoyloxy)propanesulfonate, 1,1,3,3,3-pentafluoro-2-pivaloyloxypropanesulfonate, 2-cyclohexanecarbonyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 1,1,3,3,3-pentafluoro-2-furoyloxypropanesulfonate, 2-naphthoyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 2-(4-tert-butylbenzoyloxy)-1,1,3,3,3-pentafluoropropane-sulfonate, 2-(1-adamantanecarbonyloxy)-1,1,3,3,3-pentafluoropropane-sulfonate, 2-acetyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 1,1,3,3,3-pentafluoro-2-hydroxypropanesulfonate, 1,1,3,3,3-pentafluoro-2-tosyloxypropanesulfonate, 1,1-difluoro-2-tosyloxyethanesulfonate, adamantanemethoxycarbonyldifluoromethanesulfonate, 1-(3-hydroxymethyladamantane)methoxycarbonyldifluoromethane-sulfonate, methoxycarbonyldifluoromethanesulfonate, 1-(hexahydro-2-oxo-3,5-methano-2H-cyclopenta[b]furan-6-yl-oxycarbonyl)difluoromethanesulfonate, 4-oxo-1-adamantyloxycarbonyldifluoromethanesulfonate, etc.

Nitrobenzyl sulfonate photoacid generators include 2,4-dinitrobenzyl sulfonate, 2-nitrobenzyl sulfonate, and 2,6-dinitrobenzyl sulfonate, with exemplary sulfonates including trifluoromethanesulfonate, pentafluoroethanesulfonate, heptafluoropropanesulfonate, nonafluorobutanesulfonate, tridecafluorohexanesulfonate, perfluoro(4-ethylcyclohexane)sulfonate, heptadecafluorooctanesulfonate, 2,2,2-trifluoroethanesulfonate, pentafluorobenzenesulfonate, 4-(trifluoromethyl)benzenesulfonate, 4-fluorobenzenesulfonate, mesitylenesulfonate, 2,4,6-triisopropylbenzenesulfonate, toluenesulfonate, benzenesulfonate, 4-(p-toluenesulfonyloxy)benzenesulfonate, 6-(p-toluenesulfonyloxy)naphthalene-2-sulfonate, 4-(p-toluenesulfonyloxy)naphthalene-1-sulfonate, 5-(p-toluenesulfonyloxy)naphthalene-1-sulfonate, 8-(p-toluenesulfonyloxy)naphthalene-1-sulfonate, naphthalenesulfonate, camphorsulfonate, octanesulfonate, dodecylbenzenesulfonate, butanesulfonate, methanesulfonate, 1,1-difluoro-2-naphthylethanesulfonate, 1,1,2,2-tetrafluoro-2-(norbornan-2-yl)ethanesulfonate, 1,1,2,2-tetrafluoro-2-(tetracyclo[4.4.0.1^(2,5).1^(7,10)]dodec-3-en-8-yl)ethanesulfonate, 2-benzoyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 1,1,3,3,3-pentafluoro-2-(4-phenylbenzoyloxy)propanesulfonate, 1,1,3,3,3-pentafluoro-2-pivaloyloxypropanesulfonate, 2-cyclohexanecarbonyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 1,1,3,3,3-pentafluoro-2-furoyloxypropanesulfonate, 2-naphthoyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 2-(4-tert-butylbenzoyloxy)-1,1,3,3,3-pentafluoropropane-sulfonate, 2-(1-adamantanecarbonyloxy)-1,1,3,3,3-pentafluoropropane-sulfonate, 2-acetyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 1,1,3,3,3-pentafluoro-2-hydroxypropanesulfonate, 1,1,3,3,3-pentafluoro-2-tosyloxypropanesulfonate, 1,1-difluoro-2-tosyloxyethanesulfonate, adamantanemethoxycarbonyldifluoromethanesulfonate, 1-(3-hydroxymethyladamantane)methoxycarbonyldifluoromethane-sulfonate, methoxycarbonyldifluoromethanesulfonate, 1-(hexahydro-2-oxo-3,5-methano-2H-cyclopenta[b]furan-6-yl-oxycarbonyl)difluoromethanesulfonate, 4-oxo-1-adamantyloxycarbonyldifluoromethanesulfonate, etc. Also useful are nitrobenzyl sulfonate analogues in which the nitro group on the benzyl side is substituted by a trifluoromethyl group.

Sulfone photoacid generators include bis(phenylsulfonyl)methane, bis(4-methylphenylsulfonyl)methane, bis(2-naphthylsulfonyl)methane, 2,2-bis(phenylsulfonyl)propane, 2,2-bis(4-methylphenylsulfonyl)propane, 2,2-bis(2-naphthylsulfonyl)propane, 2-methyl-2-(p-toluenesulfonyl)propiophenone, 2-cyclohexylcarbonyl-2-(p-toluenesulfonyl)propane, and 2,4-dimethyl-2-(p-toluenesulfonyl)pentan-3-one.

Suitable O-arylsulfonyloxime compounds and O-alkylsulfonyloxime compounds (oxime sulfonates) include photoacid generators in the form of glyoxime derivatives; photoacid generators in the form of oxime sulfonates with a long conjugated system separated by thiophene or cyclohexadiene; oxime sulfonates having an electron withdrawing group such as trifluoromethyl incorporated for increased stability; oxime sulfonates using phenylacetonitrile or substituted acetonitrile derivatives; and bisoxime sulfonates.

Photoacid generators in the form of glyoxime derivatives include bis-O-(p-toluenesulfonyl)-α-dimethylglyoxime, bis-O-(p-toluenesulfonyl)-α-diphenylglyoxime, bis-O-(p-toluenesulfonyl)-α-dicyclohexylglyoxime, bis-O-(p-toluenesulfonyl)-2,3-pentanedionedioxime, bis-O-(n-butanesulfonyl)-α-dimethylglyoxime, bis-O-(n-butanesulfonyl)-α-diphenylglyoxime, bis-O-(n-butanesulfonyl)-α-dicyclohexylglyoxime, bis-O-(methanesulfonyl)-α-dimethylglyoxime, bis-O-(trifluoromethanesulfonyl)-α-dimethylglyoxime, bis-O-(2,2,2-trifluoroethanesulfonyl)-α-dimethylglyoxime, bis-O-(10-camphorsulfonyl)-α-dimethylglyoxime, bis-O-(benzenesulfonyl)-α-dimethylglyoxime, bis-O-(4-fluorobenzenesulfonyl)-α-dimethylglyoxime, bis-O-(4-trifluoromethylbenzenesulfonyl)-α-dimethylglyoxime, bis-O-(xylenesulfonyl)-α-dimethylglyoxime, bis-O-(trifluoromethanesulfonyl)-nioxime, bis-O-(2,2,2-trifluoroethanesulfonyl)-nioxime, bis-O-(10-camphorsulfonyl)-nioxime, bis-O-(benzenesulfonyl)-nioxime, bis-O-(4-fluorobenzenesulfonyl)-nioxime, bis-O-(4-(trifluoromethyl)benzenesulfonyl)-nioxime, and bis-O-(xylenesulfonyl)-nioxime. Also included are modified forms of the foregoing compounds having substituted on their skeleton 2-benzoyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 1,1,3,3,3-pentafluoro-2-(4-phenylbenzoyloxy)propanesulfonate, 1,1,3,3,3-pentafluoro-2-pivaloyloxypropanesulfonate, 2-cyclohexanecarbonyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 1,1,3,3,3-pentafluoro-2-furoyloxypropanesulfonate, 2-naphthoyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 2-(4-tert-butylbenzoyloxy)-1,1,3,3,3-pentafluoropropane-sulfonate, 2-(1-adamantanecarbonyloxy)-1,1,3,3,3-pentafluoropropane-sulfonate, 2-acetyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 1,1,3,3,3-pentafluoro-2-hydroxypropanesulfonate, 1,1,3,3,3-pentafluoro-2-tosyloxypropanesulfonate, 1,1-difluoro-2-tosyloxyethanesulfonate, adamantanemethoxycarbonyldifluoromethanesulfonate, 1-(3-hydroxymethyladamantane)methoxycarbonyldifluoromethane-sulfonate, methoxycarbonyldifluoromethanesulfonate, 1-(hexahydro-2-oxo-3,5-methano-2H-cyclopenta[b]furan-6-yl-oxycarbonyl)difluoromethanesulfonate, and 4-oxo-1-adamantyloxycarbonyldifluoromethanesulfonate.

Photoacid generators in the form of oxime sulfonates with a long conjugated system separated by thiophene or cyclohexadiene include (5-(p-toluenesulfonyl)oxyimino-5H-thiophen-2-ylidene)phenyl-acetonitrile, (5-(10-camphorsulfonyl)oxyimino-5H-thiophen-2-ylidene)phenyl-acetonitrile, (5-n-octanesulfonyloxyimino-5H-thiophen-2-ylidene)phenyl-acetonitrile, (5-(p-toluenesulfonyl)oxyimino-5H-thiophen-2-ylidene)(2-methylphenyl)acetonitrile, (5-(10-camphorsulfonyl)oxyimino-5H-thiophen-2-ylidene)(2-methylphenyl)acetonitrile, (5-n-octanesulfonyloxyimino-5H-thiophen-2-ylidene)(2-methylphenyl)acetonitrile, (5-(4-(p-toluenesulfonyloxy)benzenesulfonyl)oxyimino-5H-thiophen-2-ylidene)phenylacetonitrile, and (5-(2,5-bis(p-toluenesulfonyloxy)benzenesulfonyl)oxyimino-5H-thiophen-2-ylidene)phenylacetonitrile. Also included are modified forms of the foregoing compounds having substituted on their skeleton 2-benzoyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 1,1,3,3,3-pentafluoro-2-(4-phenylbenzoyloxy)propanesulfonate, 1,1,3,3,3-pentafluoro-2-pivaloyloxypropanesulfonate, 2-cyclohexanecarbonyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 1,1,3,3,3-pentafluoro-2-furoyloxypropanesulfonate, 2-naphthoyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 2-(4-tert-butylbenzoyloxy)-1,1,3,3,3-pentafluoropropane-sulfonate, 2-(1-adamantanecarbonyloxy)-1,1,3,3,3-pentafluoropropane-sulfonate, 2-acetyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 1,1,3,3,3-pentafluoro-2-hydroxypropanesulfonate, 1,1,3,3,3-pentafluoro-2-tosyloxypropanesulfonate, 1,1-difluoro-2-tosyloxyethanesulfonate, adamantanemethoxycarbonyldifluoromethanesulfonate, 1-(3-hydroxymethyladamantane)methoxycarbonyldifluoromethane-sulfonate, methoxycarbonyldifluoromethanesulfonate, 1-(hexahydro-2-oxo-3,5-methano-2H-cyclopenta[b]furan-6-yl-oxycarbonyl)difluoromethanesulfonate, and 4-oxo-1-adamantyloxycarbonyldifluoromethanesulfonate.

Suitable oxime sulfonates having an electron withdrawing group such as trifluoromethyl incorporated for increased stability include 2,2,2-trifluoro-1-phenyl-ethanone O-(methylsulfonyl)oxime, 2,2,2-trifluoro-1-phenyl-ethanone O-(10-camphorsulfonyl)-oxime, 2,2,2-trifluoro-1-phenylethanone O-(4-methoxybenzenesulfonyl)oxime, 2,2,2-trifluoro-1-phenylethanone O-(1-naphthylsulfonyl)oxime, 2,2,2-trifluoro-1-phenylethanone O-(2-naphthylsulfonyl)oxime, 2,2,2-trifluoro-1-phenylethanone O-(2,4,6-trimethylphenylsulfonyl)oxime, 2,2,2-trifluoro-1-(4-methylphenyl)ethanone O-(10-camphorsulfonyl)oxime, 2,2,2-trifluoro-1-(4-methylphenyl)ethanone O-(methylsulfonyl)oxime, 2,2,2-trifluoro-1-(2-methylphenyl)ethanone O-(10-camphorsulfonyl)oxime, 2,2,2-trifluoro-1-(2,4-dimethylphenyl)ethanone O-(10-camphorsulfonyl)oxime, 2,2,2-trifluoro-1-(2,4-dimethylphenyl)ethanone O-(1-naphthylsulfonyl)oxime, 2,2,2-trifluoro-1-(2,4-dimethylphenyl)-ethanone O-(2-naphthylsulfonyl)oxime, 2,2,2-trifluoro-1-(2,4,6-trimethylphenyl)ethanone O-(10-camphorsulfonyl)oxime, 2,2,2-trifluoro-1-(2,4,6-trimethylphenyl)ethanone O-(1-naphthylsulfonyl)oxime, 2,2,2-trifluoro-1-(2,4,6-trimethylphenyl)ethanone O-(2-naphthylsulfonyl)oxime, 2,2,2-trifluoro-1-(4-methoxyphenyl)ethanone O-(methyl-sulfonyl)oxime, 2,2,2-trifluoro-1-(4-methylthiophenyl)-ethanone O-(methyl-sulfonyl)oxime, 2,2,2-trifluoro-1-(3,4-dimethoxyphenyl)ethanone O-(methyl-sulfonyl)oxime, 2,2,2-trifluoro-1-(4-methoxyphenyl)ethanone O-(4-methylphenylsulfonyl)oxime, 2,2,2-trifluoro-1-(4-methoxyphenyl)ethanone O-(4-methoxyphenylsulfonyl)oxime, 2,2,2-trifluoro-1-(4-methoxyphenyl)ethanone O-(4-dodecylphenylsulfonyl)oxime, 2,2,2-trifluoro-1-(4-methoxyphenyl)ethanone O-(octylsulfonyl)oxime, 2,2,2-trifluoro-1-(4-thiomethylphenyl)ethanone O-(4-methoxyphenylsulfonyl)oxime, 2,2,2-trifluoro-1-(4-thiomethylphenyl)ethanone O-(4-dodecylphenylsulfonyl)oxime, 2,2,2-trifluoro-1-(4-thiomethylphenyl)ethanone O-(octylsulfonyl)oxime, 2,2,2-trifluoro-1-(4-thiomethylphenyl)ethanone O-(2-naphthylsulfonyl)oxime, 2,2,2-trifluoro-1-(2-methylphenyl)ethanone O-(methylsulfonyl)oxime, 2,2,2-trifluoro-1-(4-methylphenyl)ethanone O-(phenylsulfonyl)oxime, 2,2,2-trifluoro-1-(4-chlorophenyl)ethanone O-(phenylsulfonyl)oxime, 2,2,3,3,4,4,4-heptafluoro-1-phenylbutanone O-(10-camphorsulfonyl)oxime, 2,2,2-trifluoro-1-(1-naphthyl)ethanone O-(methylsulfonyl)-oxime, 2,2,2-trifluoro-1-(2-naphthyl)ethanone O-(methylsulfonyl)-oxime, 2,2,2-trifluoro-1-(4-benzylphenyl)ethanone O-(methylsulfonyl)oxime, 2,2,2-trifluoro-1-(4-(phenyl-1,4-dioxa-but-1-yl)phenyl)-ethanone O-(methylsulfonyl)oxime, 2,2,2-trifluoro-1-(1-naphthyl)ethanone O-(propylsulfonyl)-oxime, 2,2,2-trifluoro-1-(2-naphthyl)ethanone O-(propylsulfonyl)-oxime, 2,2,2-trifluoro-1-(4-benzylphenyl)ethanone O-(propylsulfonyl)oxime, 2,2,2-trifluoro-1-(4-methylsulfonylphenyl)ethanone O-(propylsulfonyl)oxime, 2,2,2-trifluoro-1-(4-methylsulfonyloxyphenyl)ethanone O-(propylsulfonyl)oxime, 2,2,2-trifluoro-1-(4-methylcarbonyloxyphenyl)ethanone O-(propylsulfonyl)oxime, 2,2,2-trifluoro-1-(6H,7H-5,8-dioxonaphth-2-yl)ethanone O-(propylsulfonyl)oxime, 2,2,2-trifluoro-1-(4-methoxycarbonylmethoxyphenyl)ethanone O-(propylsulfonyl)oxime, 2,2,2-trifluoro-1-(4-methoxycarbonyl)-(4-amino-1-oxa-pent-1-yl)phenyl)ethanone O-(propylsulfonyl)oxime, 2,2,2-trifluoro-1-(3,5-dimethyl-4-ethoxyphenyl)ethanone O-(propylsulfonyl)oxime, 2,2,2-trifluoro-1-(4-benzyloxyphenyl)ethanone O-(propylsulfonyl)oxime, 2,2,2-trifluoro-1-(2-thiophenyl)ethanone O-(propylsulfonate)-oxime, and 2,2,2-trifluoro-1-(1-dioxathiophen-2-yl)ethanone O-(propylsulfonate)oxime; 2,2,2-trifluoro-1-(4-(3-(4-(2,2,2-trifluoro-1-(trifluoromethanesulfonyloxyimino)ethyl)phenoxy)propoxy)phenyl)ethanone O-(trifluoromethanesulfonyl)oxime, 2,2,2-trifluoro-1-(4-(3-(4-(2,2,2-trifluoro-1-(1-propanesulfonyloxyimino)ethyl)phenoxy)propoxy)phenyl)ethanone O-(propylsulfonyl)oxime, 2,2,2-trifluoro-1-(4-(3-(4-(2,2,2-trifluoro-1-(1-butanesulfonyloxyimino)ethyl)phenoxy)propoxy)phenyl)ethanone. O-(butylsulfonyl)oxime, 2,2,2-trifluoro-1-(4-(3-(4-(2,2,2-trifluoro-1-(4-(4-methylphenylsulfonyloxy)phenylsulfonyloxyimino)ethyl)phenoxy)-propoxy)phenyl)ethanone O-(4-(4-methylphenylsulfonyloxy)-phenylsulfonyl)oxime, and 2,2,2-trifluoro-1-(4-(3-(4-(2,2,2-trifluoro-1-(2,5-bis(4-methylphenylsulfonyloxy)benzenesulfonyloxy)phenylsulfonyl-oxyimino)ethyl)phenoxy)propoxy)phenyl)ethanone O-(2,5-bis(4-methylphenylsulfonyloxy)benzenesulfonyloxy)phenylsulfonyl)-oxime.

Also included are modified forms of the foregoing compounds having substituted on their skeleton 2-benzoyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 1,1,3,3,3-pentafluoro-2-(4-phenylbenzoyloxy)propanesulfonate, 1,1,3,3,3-pentafluoro-2-pivaloyloxypropanesulfonate, 2-cyclohexanecarbonyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 1,1,3,3,3-pentafluoro-2-furoyloxypropanesulfonate, 2-naphthoyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 2-(4-tert-butylbenzoyloxy)-1,1,3,3,3-pentafluoropropanesulfonate, 2-(1-adamantanecarbonyloxy)-1,1,3,3,3-pentafluoropropanesulfonate, 2-acetyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 1,1,3,3,3-pentafluoro-2-hydroxypropanesulfonate, 1,1,3,3,3-pentafluoro-2-tosyloxypropanesulfonate, 1,1-difluoro-2-tosyloxyethanesulfonate, adamantanemethoxycarbonyldifluoromethanesulfonate, 1-(3-hydroxymethyladamantane)methoxycarbonyldifluoromethanesulfonate, methoxycarbonyldifluoromethanesulfonate, 1-(hexahydro-2-oxo-3,5-methano-2H-cyclopenta[b]furan-6-yl-oxycarbonyl)difluoromethanesulfonate, and 4-oxo-1-adamantyloxycarbonyldifluoromethanesulfonate.

Also included are oxime sulfonates having the formula (Ox-1):

wherein R⁴⁰¹ is a substituted or unsubstituted C₁-C₁₀ haloalkylsulfonyl or halobenzenesulfonyl group, R⁴⁰² is a C₁-C₁₁ haloalkyl group, and Ar⁴⁰¹ is substituted or unsubstituted aromatic or hetero-aromatic group.

Examples include 2-[2,2,3,3,4,4,5,5-octafluoro-1-(nonafluorobutylsulfonyloxyimino)-pentyl]fluorene, 2-[2,2,3,3,4,4-pentafluoro-1-(nonafluorobutylsulfonyloxyimino)-butyl]fluorene, 2-[2,2,3,3,4,4,5,5,6,6-decafluoro-1-(nonafluorobutylsulfonyloxyimino)-hexyl]fluorene, 2-[2,2,3,3,4,4,5,5-octafluoro-1-(nonafluorobutylsulfonyloxyimino)-pentyl]-4-biphenyl, 2-[2,2,3,3,4,4-pentafluoro-1-(nonafluorobutylsulfonyloxyimino)-butyl]-4-biphenyl, and 2-[2,2,3,3,4,4,5,5,6,6-decafluoro-1-(nonafluorobutylsulfonyloxyimino)-hexyl]-4-biphenyl.

Also included are modified forms of the foregoing compounds having substituted on their skeleton 2-benzoyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 1,1,3,3,3-pentafluoro-2-(4-phenylbenzoyloxy)propanesulfonate, 1,1,3,3,3-pentafluoro-2-pivaloyloxypropanesulfonate, 2-cyclohexanecarbonyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 1,1,3,3,3-pentafluoro-2-furoyloxypropanesulfonate, 2-naphthoyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 2-(4-tert-butylbenzoyloxy)-1,1,3,3,3-pentafluoropropanesulfonate, 2-(1-adamantanecarbonyloxy)-1,1,3,3,3-pentafluoropropanesulfonate, 2-acetyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 1,1,3,3,3-pentafluoro-2-hydroxypropanesulfonate, 1,1,3,3,3-pentafluoro-2-tosyloxypropanesulfonate, 1,1-difluoro-2-tosyloxyethanesulfonate, adamantanemethoxycarbonyldifluoromethanesulfonate, 1-(3-hydroxymethyladamantane)methoxycarbonyldifluoromethanesulfonate, methoxycarbonyldifluoromethanesulfonate, 1-(hexahydro-2-oxo-3,5-methano-2H-cyclopenta[b]furan-6-yl-oxycarbonyl)difluoromethanesulfonate, and 4-oxo-1-adamantyloxycarbonyldifluoromethanesulfonate.

Suitable oxime sulfonate generators using substituted acetonitrile derivatives include α-(p-toluenesulfonyloxyimino)-phenylacetonitrile, α-(p-chlorobenzenesulfonyloxyimino)-phenylacetonitrile, α-(4-nitrobenzenesulfonyloxyimino)-phenylacetonitrile, α-(4-nitro-2-trifluoromethylbenzenesulfonyloxyimino)-phenylacetonitrile, α-(benzenesulfonyloxyimino)-4-chlorophenylacetonitrile, α-(benzenesulfonyloxyimino)-2,4-dichlorophenylacetonitrile, α-(benzenesulfonyloxyimino)-2,6-dichlorophenylacetonitrile, α-(benzenesulfonyloxyimino)-4-methoxyphenylacetonitrile, α-(2-chlorobenzenesulfonyloxyimino)-4-methoxyphenylacetonitrile, α-(benzenesulfonyloxyimino)-2-thienylacetonitrile, α-(4-dodecylbenzenesulfonyloxyimino)-phenylacetonitrile, α-[(4-toluenesulfonyloxyimino)-4-methoxyphenyl]acetonitrile, α-[(dodecylbenzenesulfonyloxyimino)-4-methoxyphenyl]-acetonitrile, α-(tosyloxyimino)-3-thienylacetonitrile, α-(methylsulfonyloxyimino)-1-cyclopentenylacetonitrile, α-(ethylsulfonyloxyimino)-1-cyclopentenylacetonitrile, α-(isopropylsulfonyloxyimino)-1-cyclopentenylacetonitrile, α-(n-butylsulfonyloxyimino)-1-cyclopentenylacetonitrile, α-(ethylsulfonyloxyimino)-1-cyclohexenylacetonitrile, α-(isopropylsulfonyloxyimino)-1-cyclohexenylacetonitrile, and α-(n-butylsulfonyloxyimino)-1-cyclohexenylacetonitrile. Also included are modified forms of the foregoing compounds having substituted on their skeleton 2-benzoyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 1,1,3,3,3-pentafluoro-2-(4-phenylbenzoyloxy)propanesulfonate, 1,1,3,3,3-pentafluoro-2-pivaloyloxypropanesulfonate, 2-cyclohexanecarbonyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 1,1,3,3,3-pentafluoro-2-furoyloxypropanesulfonate, 2-naphthoyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 2-(4-tert-butylbenzoyloxy)-1,1,3,3,3-pentafluoropropanesulfonate, 2-(1-adamantanecarbonyloxy)-1,1,3,3,3-pentafluoropropanesulfonate, 2-acetyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 1,1,3,3,3-pentafluoro-2-hydroxypropanesulfonate, 1,1,3,3,3-pentafluoro-2-tosyloxypropanesulfonate, 1,1-difluoro-2-tosyloxyethanesulfonate, adamantanemethoxycarbonyldifluoromethanesulfonate, 1-(3-hydroxymethyladamantane)methoxycarbonyldifluoromethanesulfonate, methoxycarbonyldifluoromethanesulfonate, 1-(hexahydro-2-oxo-3,5-methano-2H-cyclopenta[b]furan-⁶-yl-oxycarbonyl)difluoromethanesulfonate, and 4-oxo-1-adamantyloxycarbonyldifluoromethanesulfonate.

Suitable bisoxime sulfonates include bis(α-(p-toluenesulfonyloxy)imino)-p-phenylenediacetonitrile, bis(α-(benzenesulfonyloxy)imino)-p-phenylenediacetonitrile, bis(α-(methanesulfonyloxy)imino)-p-phenylenediacetonitrile, bis(α-(butanesulfonyloxy)imino)-p-phenylenediacetonitrile, bis(α-(10-camphorsulfonyloxy)imino)-p-phenylenediacetonitrile, bis(α-(trifluoromethanesulfonyloxy)imino)-p-phenylenediacetonitrile, bis(α-(4-methoxybenzenesulfonyloxy)imino)-p-phenylenediacetonitrile, bis(α-(4-toluenesulfonyloxy)imino)-m-phenylenediacetonitrile, bis(α-(benzenesulfonyloxy)imino)-m-phenylenediacetonitrile, bis(α-(methanesulfonyloxy)imino)-m-phenylenediacetonitrile, bis(α-(butanesulfonyloxy)imino)-m-phenylenediacetonitrile, bis(α-(10-camphorsulfonyloxy)imino)-m-phenylenediacetonitrile, bis(α-(trifluoromethanesulfonyloxy)imino)-m-phenylenediacetonitrile, bis(α-(4-methoxybenzenesulfonyloxy)imino)-m-phenylenediacetonitrile, etc.

Also included are modified forms of the foregoing compounds having substituted on their skeleton 2-benzoyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 1,1,3,3,3-pentafluoro-2-(4-phenylbenzoyloxy)propanesulfonate, 1,1,3,3,3-pentafluoro-2-pivaloyloxypropanesulfonate, 2-cyclohexanecarbonyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 1,1,3,3,3-pentafluoro-2-furoyloxypropanesulfonate, 2-naphthoyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 2-(4-tert-butylbenzoyloxy)-1,1,3,3,3-pentafluoropropanesulfonate, 2-(1-adamantanecarbonyloxy)-1,1,3,3,3-pentafluoropropanesulfonate, 2-acetyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 1,1,3,3,3-pentafluoro-2-hydroxypropanesulfonate, 1,1,3,3,3-pentafluoro-2-tosyloxypropanesulfonate, 1,1-difluoro-2-tosyloxyethanesulfonate, adamantanemethoxycarbonyldifluoromethanesulfonate, 1-(3-hydroxymethyladamantane)methoxycarbonyldifluoromethanesulfonate, methoxycarbonyldifluoromethanesulfonate, 1-(hexahydro-2-oxo-3,5-methano-2H-cyclopenta[b]furan-6-yl-oxycarbonyl)difluoromethanesulfonate, and 4-oxo-1-adamantyloxycarbonyldifluoromethanesulfonate.

When the photoacid generator (B) is added to the KrF excimer laser resist composition, preference is given to sulfonium salts, bissulfonyldiazomethanes, N-sulfonyloxyimides and oxime-O-sulfonates. Illustrative preferred photoacid generators include triphenylsulfonium p-toluenesulfonate, triphenylsulfonium camphorsulfonate, triphenylsulfonium pentafluorobenzenesulfonate, triphenylsulfonium nonafluorobutanesulfonate, triphenylsulfonium 4-(p-toluenesulfonyloxy)benzenesulfonate, triphenylsulfonium 2,4,6-triisopropylbenzenesulfonate, 4-tert-butoxyphenyldiphenylsulfonium p-toluenesulfonate, 4-tert-butoxyphenyldiphenylsulfonium camphorsulfonate, 4-tert-butoxyphenyldiphenylsulfonium 4-(p-toluenesulfonyloxy)benzenesulfonate, 4-tert-butylphenyldiphenylsulfonium camphorsulfonate, tris(4-methylphenyl)sulfonium camphorsulfonate, tris(4-tert-butylphenyl)sulfonium camphorsulfonate, bis(tert-butylsulfonyl)diazomethane, bis(cyclohexylsulfonyl)diazomethane, bis(2,4-dimethylphenylsulfonyl)diazomethane, bis(4-n-hexyloxyphenylsulfonyl)diazomethane, bis(2-methyl-4-n-hexyloxyphenylsulfonyl)diazomethane, bis(2,5-dimethyl-4-n-hexyloxyphenylsulfonyl)diazomethane, bis(3,5-dimethyl-4-n-hexyloxyphenylsulfonyl)diazomethane, bis(2-methyl-5-isopropyl-4-n-hexyloxy)phenylsulfonyldiazomethane, bis(4-tert-butylphenylsulfonyl)diazomethane, N-camphorsulfonyloxy-5-norbornene-2,3-dicarboxylic acid imide, N-p-toluenesulfonyloxy-5-norbornene-2,3-dicarboxylic acid imide, (5-(10-camphorsulfonyl)oxyimino-5H-thiophen-2-ylidene)(2-methylphenyl)acetonitrile, and (5-(p-toluenesulfonyl)oxyimino-5H-thiophen-2-ylidene)(2-methylphenyl)acetonitrile.

When the photoacid generator (B) is added to the ArF laser resist composition, preference is given to sulfonium salts and oxime-O-sulfonates. Illustrative preferred photoacid generators include triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium pentafluoroethanesulfonate, triphenylsulfonium heptafluoropropanesulfonate, triphenylsulfonium nonafluorobutanesulfonate, triphenylsulfonium tridecafluorohexanesulfonate, triphenylsulfonium heptadecafluorooctanesulfonate, triphenylsulfonium perfluoro(4-ethylcyclohexane)sulfonate, 4-methylphenyldiphenylsulfonium nonafluorobutanesulfonate, 2-oxo-2-phenylethylthiacyclopentanium nonafluorobutanesulfonate, 4-tert-butylphenyldiphenylsulfonium nonafluorobutanesulfonate, 4-tert-butylphenyldiphenylsulfonium perfluoro(4-ethylcyclohexane)sulfonate, 4-tert-butylphenyldiphenylsulfonium heptafluorooctanesulfonate, triphenylsulfonium 1,1-difluoro-2-naphthylethanesulfonate, triphenylsulfonium 1,1,2,2-tetrafluoro-2-(norbornan-2-yl)-ethanesulfonate, triphenylsulfonium 2-benzoyloxy-1,1,3,3,3-pentafluoropropanesulfonate, triphenylsulfonium 1,1,3,3,3-pentafluoro-2-(pivaloyloxy)-propanesulfonate, triphenylsulfonium 2-(cyclohexanecarbonyloxy)-1,1,3,3,3-pentafluoropropanesulfonate, triphenylsulfonium 2-(2-naphthoyloxy)-1,1,3,3,3-pentafluoropropanesulfonate, triphenylsulfonium 2-(1-adamantanecarbonyloxy)-1,1,3,3,3-pentafluoropropanesulfonate, triphenylsulfonium 2-hydroxy-1,1,3,3,3-pentafluoropropanesulfonate, triphenylsulfonium adamantanemethoxycarbonyldifluoromethanesulfonate, triphenylsulfonium 1-(3-hydroxymethyladamantane)methoxycarbonyldifluoromethanesulfonate, triphenylsulfonium methoxycarbonyldifluoromethanesulfonate, 4-tert-butylphenyldiphenylsulfonium 2-benzoyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 4-tert-butylphenyldiphenylsulfonium 1,1,3,3,3-pentafluoro-2-(pivaloyloxy)propanesulfonate, 4-tert-butylphenyldiphenylsulfonium 2-(cyclohexanecarbonyloxy)-1,1,3,3,3-pentafluoropropanesulfonate, 4-tert-butylphenyldiphenylsulfonium 2-(2-naphthoyloxy)-1,1,3,3,3-pentafluoropropanesulfonate, 4-tert-butylphenyldiphenylsulfonium 2-(1-adamantanecarbonyloxy)-1,1,3,3,3-pentafluoropropanesulfonate, 4-tert-butylphenyldiphenylsulfonium 2-hydroxy-1,1,3,3,3-pentafluoropropanesulfonate, 4-tert-butylphenyldiphenylsulfonium adamantanemethoxycarbonyldifluoromethanesulfonate, 4-tert-butylphenyldiphenylsulfonium 1-(3-hydroxymethyladamantane)methoxycarbonyldifluoromethanesulfonate, 4-tert-butylphenyldiphenylsulfonium methoxycarbonyldifluoromethanesulfonate, 2-oxo-2-phenylethylthiacyclopentanium 2-benzoyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 2-oxo-2-phenylethylthiacyclopentanium 2-cyclohexanecarbonyloxy)-1,1,3,3,3-pentafluoropropanesulfonate, triphenylsulfonium perfluoro(1,3-propylenebissulfonyl)imide, triphenylsulfonium bis(pentafluoroethylsulfonyl)imide, 2-(2,2,3,3,4,4,5,5-octafluoro-1-(nonafluorobutylsulfonyloxyimino)pentyl)fluorene, 2-(2,2,3,3,4,4-pentafluoro-1-(nonafluorobutylsulfonyloxyimino)butyl)fluorene, 2-(2,2,3,3,4,4,5,5,6,6-decafluoro-1-(nonafluorobutylsulfonyloxyimino)hexyl)fluorene, 2-(2,2,3,3,4,4,5,5-octafluoro-1-(2-(cyclohexanecarbonyloxy)-1,1,3,3,3-pentafluoropropanesulfonyloxyimino)pentyl)fluorene, 2-(2,2,3,3,4,4-pentafluoro-1-(2-(cyclohexanecaronyloxy)-1,1,3,3,3-pentafluoropropanesulfonyloxyimino)butyl)fluorene, and 2-(2,2,3,3,4,4,5,5,6,6-decafluoro-1-(nonafluorobutylsulfonyloxyimino)hexyl)fluorene.

When the photoacid generator (B) is added to the ArF immersion lithography resist composition, preference is given to sulfonium salts and oxime-O-sulfonates. Illustrative preferred photoacid generators include triphenylsulfonium nonafluorobutanesulfonate, triphenylsulfonium tridecafluorohexanesulfonate, triphenylsulfonium heptadecafluorooctanesulfonate, triphenylsulfonium perfluoro(4-ethylcyclohexane)sulfonate, 4-methylphenyldiphenylsulfonium nonafluorobutanesulfonate, 2-oxo-2-phenylethylthiacyclopentanium nonafluorobutanesulfonate, 4-tert-butylphenyldiphenylsulfonium nonafluorobutanesulfonate, 4-tert-butylphenyldiphenylsulfonium perfluoro(4-ethylcyclohexane)sulfonate, 4-tert-butylphenyldiphenylsulfonium heptafluorooctanesulfonate, triphenylsulfonium 1,1-difluoro-2-naphthylethanesulfonate, triphenylsulfonium 1,1,2,2-tetrafluoro-2-(norbornan-2-yl)-ethanesulfonate, triphenylsulfonium 2-benzoyloxy-1,1,3,3,3-pentafluoropropanesulfonate, triphenylsulfonium 1,1,3,3,3-pentafluoro-2-(pivaloyloxy)-propanesulfonate, triphenylsulfonium 2-(cyclohexanecarbonyloxy)-1,1,3,3,3-pentafluoropropanesulfonate, triphenylsulfonium 2-(2-naphthoyloxy)-1,1,3,3,3-pentafluoropropanesulfonate, triphenylsulfonium 2-(1-adamantanecarbonyloxy)-1,1,3,3,3-pentafluoropropanesulfonate, triphenylsulfonium 2-hydroxy-1,1,3,3,3-pentafluoropropanesulfonate, triphenylsulfonium adamantanemethoxycarbonyldifluoromethanesulfonate, triphenylsulfonium 1-(3-hydroxymethyladamantane)methoxycarbonyldifluoromethanesulfonate, triphenylsulfonium methoxycarbonyldifluoromethanesulfonate, 4-tert-butylphenyldiphenylsulfonium 2-benzoyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 4-tert-butylphenyldiphenylsulfonium 1,1,3,3,3-pentafluoro-2-(pivaloyloxy)propanesulfonate, 4-tert-butylphenyldiphenylsulfonium 2-(cyclohexanecarbonyl-oxy)-1,1,3,3,3-pentafluoropropanesulfonate, 4-tert-butylphenyldiphenylsulfonium 2-(2-naphthoyloxy)-1,1,3,3,3-pentafluoropropanesulfonate, 4-tert-butylphenyldiphenylsulfonium 2-(1-adamantanecarbonyloxy)-1,1,3,3,3-pentafluoropropanesulfonate, 4-tert-butylphenyldiphenylsulfonium 2-hydroxy-1,1,3,3,3-pentafluoropropanesulfonate, 4-tert-butylphenyldiphenylsulfonium adamantanemethoxycarbonyldifluoromethanesulfonate, 4-tert-butylphenyldiphenylsulfonium 1-(3-hydroxymethyladamantane)methoxycarbonyldifluoromethanesulfonate, 4-tert-butylphenyldiphenylsulfonium methoxycarbonyldifluoromethanesulfonate, 2-oxo-2-phenylethylthiacyclopentanium 2-benzoyloxy-1,1,3,3,3-pentafluoropropanesulfonate, 2-oxo-2-phenylethylthiacyclopentanium 2-cyclohexanecarbonyloxy-1,1,3,3,3-pentafluoropropanesulfonate, triphenylsulfonium perfluoro(1,3-propylenebissulfonyl)imide, triphenylsulfonium bis(pentafluoroethylsulfonyl)imide, 2-(2,2,3,3,4,4,5,5-octafluoro-1-(nonafluorobutylsulfonyloxyimino)pentyl)fluorene, 2-(2,2,3,3,4,4-pentafluoro-1-(nonafluorobutylsulfonyloxyimino)butyl)fluorene, 2-(2,2,3,3,4,4,5,5,6,6-decafluoro-1-(nonafluorobutylsulfonyloxyimino)hexyl)fluorene, 2-(2,2,3,3,4,4,5,5-octafluoro-1-(2-(cyclohexanecarbonyloxy)-1,1,3,3,3-pentafluoropropanesulfonyloxyimino)pentyl)fluorene, 2-(2,2,3,3,4,4-pentafluoro-1-(2-(cyclohexanecarbonyloxy)-1,1,3,3,3-pentafluoropropanesulfonyloxyimino)butyl)fluorene, and 2-(2,2,3,3,4,4,5,5,6,6-decafluoro-1-(nonafluorobutylsulfonyloxyimino)hexyl)fluorene.

In the chemically amplified resist composition, the photoacid generator (B) may be added in any desired amount as long as the objects of the invention are not compromised. An appropriate amount of the photoacid generator (B) is 0.1 to 10 parts, and more preferably 0.1 to 5 parts by weight per 100 parts by weight of the base resin in the composition. Too high a proportion of the photoacid generator (B) may give rise to problems of degraded resolution and foreign matter upon development and resist film peeling. The photoacid generators may be used alone or in admixture of two or more. The transmittance of the resist film can be controlled by using an photoacid generator having a low transmittance at the exposure wavelength and adjusting the amount of the photoacid generator added.

It is noted that an acid diffusion controlling function may be provided when two or more photoacid generators are used in admixture provided that one photoacid generator is an onium salt capable of generating a weak acid. Specifically, in a system using a mixture of a photoacid generator capable of generating a strong acid (e.g., fluorinated sulfonic acid) and an onium salt capable of generating a weak acid (e.g., non-fluorinated sulfonic acid or carboxylic acid), if the strong acid generated from the photoacid generator upon exposure to high-energy radiation collides with the unreacted onium salt having a weak acid anion, then a salt exchange occurs whereby the weak acid is released and an onium salt having a strong acid anion is formed. In this course, the strong acid is exchanged into the weak acid having a low catalysis, incurring apparent deactivation of the acid for enabling to control acid diffusion.

If an onium salt capable of generating a strong acid and an onium salt capable of generating a weak acid are used in admixture, an exchange from the strong acid to the weak acid as above can take place, but it never happens that the weak acid collides with the unreacted onium salt capable of generating a strong acid to induce a salt exchange. This is because of a likelihood of an onium cation forming an ion pair with a stronger acid anion.

In the resist composition of the invention, there may be added a compound which is decomposed with an acid to generate another acid, that is, acid amplifier compound. For these compounds, reference should be made to J. Photopolym. Sci. and Tech., 8, 43-44, 45-46 (1995), and ibid., 9, 29-30 (1996).

Examples of the acid amplifier compound include tert-butyl-2-methyl-2-tosyloxymethyl acetoacetate and 2-phenyl-2-(2-tosyloxyethyl)-1,3-dioxolane, but are not limited thereto. Of well-known photoacid generators, many of those compounds having poor stability, especially poor thermal stability exhibit an acid amplifier-like behavior.

In the resist composition of the invention, an appropriate amount of the acid amplifier compound is up to 2 parts, and especially up to 1 part by weight per 100 parts by weight of the base resin. Excessive amounts of the acid amplifier compound make diffusion control difficult, leading to degradation of resolution and pattern profile.

Organic solvent

The organic solvent (C) used herein may be any organic solvent in which the base resin, acid generator, and other components are soluble. Illustrative, non-limiting, examples of the organic solvent include ketones such as cyclohexanone and methyl amyl ketone; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, and 1-ethoxy-2-propanol; ethers such as propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether; esters such as propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, and propylene glycol mono-tert-butyl ether acetate; and lactones such as γ-butyrolactone. These solvents may be used alone or in combinations of two or more thereof. Of the above organic solvents, it is recommended to use diethylene glycol dimethyl ether, 1-ethoxy-2-propanol, propylene glycol monomethyl ether acetate, and mixtures thereof because the acid generator is most soluble therein.

An appropriate amount of the organic solvent used is about 200 to 1,000 parts, especially about 400 to 800 parts by weight per 100 parts by weight of the base resin.

Quencher

A quencher (D) may be optionally used in the resist composition of the invention. The term “quencher” as used herein has a meaning generally known in the art and refers to a compound capable of suppressing the rate of diffusion when the acid generated by the acid generator diffuses within the resist film. The inclusion of quencher facilitates adjustment of resist sensitivity and holds down the rate of acid diffusion within the resist film, resulting in better resolution. In addition, it suppresses changes in sensitivity following exposure and reduces substrate and environment dependence, as well as improving the exposure latitude and the pattern profile.

Examples of suitable quenchers include primary, secondary, and tertiary aliphatic amines, mixed amines, aromatic amines, heterocyclic amines, nitrogen-containing compounds with carboxyl group, nitrogen-containing compounds with sulfonyl group, nitrogen-containing compounds with hydroxyl group, nitrogen-containing compounds with hydroxyphenyl group, alcoholic nitrogen-containing compounds, amide derivatives, imide derivatives, carbamate derivatives, and ammonium salts.

Examples of suitable primary aliphatic amines include ammonia, methylamine, ethylamine, n-propylamine, isopropylamine, n-butylamine, isobutylamine, sec-butylamine, tert-butylamine, pentylamine, tert-amylamine, cyclopentylamine, hexylamine, cyclohexylamine, heptylamine, octylamine, nonylamine, decylamine, dodecylamine, cetylamine, methylenediamine, ethylenediamine, and tetraethylenepentamine. Examples of suitable secondary aliphatic amines include dimethylamine, diethylamine, di-n-propylamine, diisopropylamine, di-n-butylamine, diisobutylamine, di-sec-butylamine, dipentylamine, dicyclopentylamine, dihexylamine, dicyclohexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, didodecylamine, dicetylamine, N,N-dimethylmethylenediamine, N,N-dimethylethylenediamine, and N,N-dimethyltetraethylenepentamine. Examples of suitable tertiary aliphatic amines include trimethylamine, triethylamine, tri-n-propylamine, triisopropylamine, tri-n-butylamine, triisobutylamine, tri-sec-butylamine, tripentylamine, tricyclopentylamine, trihexylamine, tricyclohexylamine, triheptylamine, trioctylamine, trinonylamine, tridecylamine, tridodecylamine, tricetylamine, N,N,N′,N′-tetramethylmethylenediamine, N,N,N′,N′-tetramethylethylenediamine, and N,N,N′,N′-tetramethyltetraethylenepentamine.

Examples of suitable mixed amines include dimethylethylamine, methylethylpropylamine, benzylamine, phenethylamine, and benzyldimethylamine. Examples of suitable aromatic and heterocyclic amines include aniline derivatives (e.g., aniline, N-methylaniline, N-ethylaniline, N-propylaniline, N,N-dimethylaniline, N,N-bis(hydroxyethyl)aniline, 2-methylaniline, 3-methylaniline, 4-methylaniline, ethylaniline, propylaniline, dimethylaniline, 2,6-diisopropylaniline, trimethylaniline, 2-nitroaniline, 3-nitroaniline, 4-nitroaniline, 2,4-dinitroaniline, 2,6-dinitroaniline, 3,5-dinitroaniline, and N,N-dimethyltoluidine), diphenyl(p-tolyl)amine, methyldiphenylamine, triphenylamine, phenylenediamine, naphthylamine, diaminonaphthalene, pyrrole derivatives (e.g., pyrrole, 2H-pyrrole, 1-methylpyrrole, 2,4-dimethylpyrrole, 2,5-dimethylpyrrole, and N-methylpyrrole), oxazole derivatives (e.g., oxazole and isooxazole), thiazole derivatives (e.g., thiazole and isothiazole), imidazole derivatives (e.g., imidazole, 4-methylimidazole, and 4-methyl-2-phenylimidazole), pyrazole derivatives, furazane derivatives, pyrroline derivatives (e.g., pyrroline and 2-methyl-1-pyrroline), pyrrolidine derivatives (e.g., pyrrolidine, N-methylpyrrolidine, pyrrolidinone, and N-methylpyrrolidone), imidazoline derivatives, imidazolidine derivatives, pyridine derivatives (e.g., pyridine, methylpyridine, ethylpyridine, propylpyridine, butylpyridine, 4-(1-butylpentyl)pyridine, dimethylpyridine, trimethylpyridine, triethylpyridine, phenylpyridine, 3-methyl-2-phenylpyridine, 4-tert-butylpyridine, diphenylpyridine, benzylpyridine, methoxypyridine, butoxypyridine, dimethoxypyridine, 4-pyrrolidinopyridine, 2-(1-ethylpropyl)pyridine, aminopyridine, and dimethylaminopyridine), pyridazine derivatives, pyrimidine derivatives, pyrazine derivatives, pyrazoline derivatives, pyrazolidine derivatives, piperidine derivatives, piperazine derivatives, morpholine derivatives, indole derivatives, isoindole derivatives, 1H-indazole derivatives, indoline derivatives, quinoline derivatives (e.g., quinoline and 3-quinolinecarbonitrile), isoquinoline derivatives, cinnoline derivatives, quinazoline derivatives, quinoxaline derivatives, phthalazine derivatives, purine derivatives, pteridine derivatives, carbazole derivatives, phenanthridine derivatives, acridine derivatives, phenazine derivatives, 1,10-phenanthroline derivatives, adenine derivatives, adenosine derivatives, guanine derivatives, guanosine derivatives, uracil derivatives, and uridine derivatives.

Examples of suitable nitrogen-containing compounds with carboxyl group include aminobenzoic acid, indolecarboxylic acid, and amino acid derivatives (e.g. nicotinic acid, alanine, alginine, aspartic acid, glutamic acid, glycine, histidine, isoleucine, glycylleucine, leucine, methionine, phenylalanine, threonine, lysine, 3-aminopyrazine-2-carboxylic acid, and methoxyalanine). A typical nitrogen-containing compound with sulfonyl group is 3-pyridinesulfonic acid. Examples of suitable nitrogen-containing compounds with hydroxyl group, nitrogen-containing compounds with hydroxyphenyl group, and alcoholic nitrogen-containing compounds include 2-hydroxypyridine, aminocresol, 2,4-quinolinediol, 3-indolemethanol hydrate, monoethanolamine, diethanolamine, triethanolamine, N-ethyldiethanolamine, N,N-diethylethanolamine, triisopropanolamine, 2,2′-iminodiethanol, 2-aminoethanol, 3-amino-1-propanol, 4-amino-1-butanol, 4-(2-hydroxyethyl)morpholine, 2-(2-hydroxyethyl)pyridine, 1-(2-hydroxyethyl)piperazine, 1-[2-(2-hydroxyethoxy)ethyl]piperazine, piperidine ethanol, 1-(2-hydroxyethyl)pyrrolidine, 1-(2-hydroxyethyl)-2-pyrrolidinone, 3-piperidino-1,2-propanediol, 3-pyrrolidino-1,2-propanediol, 8-hydroxyjulolidine, 3-quinuclidinol, 3-tropanol, 1-methyl-2-pyrrolidine ethanol, 1-aziridine ethanol, N-(2-hydroxyethyl)phthalimide, and N-(2-hydroxyethyl)isonicotinamide. Examples of suitable amide derivatives include formamide, N-methylformamide, N,N-dimethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, propionamide, benzamide, and 1-cyclohexylpyrrolidone. Suitable imide derivatives include phthalimide, succinimide, and maleimide. Suitable carbamate derivatives include N-tert-butoxycarbonyl-N,N-dicyclohexylamine, N-tert-butoxycarbonylbenzimidazole, and oxazolidinone.

Suitable ammonium salts include pyridinium p-toluenesulfonate, triethylammonium p-toluenesulfonate, trioctylammonium p-toluenesulfonate, triethylammonium 2,4,6-triisopropylbenzenesulfonate, trioctylammonium 2,4,6-triisopropylbenzenesulfonate, triethylammonium camphorsulfonate, trioctylammonium camphorsulfonate, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, benzyltrimethylammonium hydroxide, tetramethylammonium p-toluenesulfonate, tetrabutylammonium p-toluenesulfonate, benzyltrimethylammonium p-toluenesulfonate, tetramethylammonium camphorsulfonate, tetrabutylammonium camphorsulfonate, benzyltrimethylammonium camphorsulfonate, tetramethylammonium 2,4,6-triisopropylbenzenesulfonate, tetrabutylammonium 2,4,6-triisopropylbenzenesulfonate, benzyltrimethylammonium 2,4,6-triisopropylbenzenesulfonate, tetramethylammonium acetate, tetrabutylammonium acetate, benzyltrimethylammonium acetate, tetramethylammonium benzoate, tetrabutylammonium benzoate, and benzyltrimethylammonium benzoate.

In addition, amine compounds of the following general formula (B)-1 may also be included alone or in admixture.

N(X)_(n)(Y)_(3-n)   (B)-1

In the formula, n is equal to 1, 2 or 3. The side chain X is independently selected from groups of the following general formulas (X)-1 to (X)-3. The side chain Y is independently hydrogen or a straight, branched or cyclic C₁-C₂₀ alkyl group in which some or all hydrogen atoms may be substituted by fluorine atoms and which may contain an ether or hydroxyl group. Two or three X may bond together to form a ring.

In the formulas, R³⁰⁰, R³⁰² and R³⁰⁵ are independently straight or branched C₁-C₄ alkylene groups; R³⁰¹ and R³⁰⁴ are independently hydrogen or straight, branched or cyclic C₁-C₂₀ alkyl groups in which some or all hydrogen atoms may be substituted by fluorine atoms and which may contain at least one hydroxyl group, ether group, ester group or lactone ring; R³⁰³ is a single bond or a straight or branched C₁-C₄ alkylene group; R³⁰⁶ is a straight, branched or cyclic C₁-C₂₀ alkyl group in which some or all hydrogen atoms may be substituted by fluorine atoms and which may contain at least one hydroxyl group, ether group, ester group or lactone ring.

Illustrative examples of the compounds of formula (B)-1 include, but are not limited to, tris(2-methoxymethoxyethyl)amine, tris{(2-(2-methoxyethoxy)ethyl}amine, tris{2-(2-methoxyethoxymethoxy)ethyl}amine, tris{2-(1-methoxyethoxy)ethyl}amine, tris{2-(1-ethoxyethoxy)ethyl}amine, tris{2-(1-ethoxypropoxy)ethyl}amine, tris[2-{2-(2-hydroxyethoxy)ethoxy}ethyl]amine, 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane, 4,7,13,18-tetraoxa-1,10-diazabicyclo[8.5.5]eicosane, 1,4,10,13-tetraoxa-7,16-diazabicyclooctadecane, 1-aza-12-crown-4,1-aza-15-crown-5,1-aza-18-crown-6, tris(2-formyloxyethyl)amine, tris(2-acetoxyethyl)amine, tris(2-propionyloxyethyl)amine, tris(2-butyryloxyethyl)amine, tris(2-isobutyryloxyethyl)amine, tris(2-valeryloxyethyl)amine, tris(2-pivaloyloxyethyl)amine, N,N-bis(2-acetoxyethyl)-2-(acetoxyacetoxy)ethylamine, tris(2-methoxycarbonyloxyethyl)amine, tris(2-tert-butoxycarbonyloxyethyl)amine, tris[2-(2-oxopropoxy)ethyl]amine, tris[2-(methoxycarbonylmethyl)oxyethyl]amine, tris[2-(tert-butoxycarbonylmethyloxy)ethyl]amine, tris[2-(cyclohexyloxycarbonylmethyloxy)ethyl]amine, tris(2-methoxycarbonylethyl)amine, tris(2-ethoxycarbonylethyl)amine, N,N-bis(2-hydroxyethyl)-2-(methoxycarbonyl)ethylamine, N,N-bis(2-acetoxyethyl)-2-(methoxycarbonyl)ethylamine, N,N-bis(2-hydroxyethyl)-2-(ethoxycarbonyl)ethylamine, N,N-bis(2-acetoxyethyl)-2-(ethoxycarbonyl)ethylamine, N,N-bis(2-hydroxyethyl)-2-(2-methoxyethoxycarbonyl)ethylamine, N,N-bis(2-acetoxyethyl)-2-(2-methoxyethoxycarbonyl)ethylamine, N,N-bis(2-hydroxyethyl)-2-(2-hydroxyethoxycarbonyl)ethylamine, N,N-bis(2-acetoxyethyl)-2-(2-acetoxyethoxycarbonyl)ethylamine, N,N-bis(2-hydroxyethyl)-2-[(methoxycarbonyl)methoxycarbonyl]-ethylamine, N,N-bis(2-acetoxyethyl)-2-[(methoxycarbonyl)methoxycarbonyl]-ethylamine, N,N-bis(2-hydroxyethyl)-2-(2-oxopropoxycarbonyl)ethylamine, N,N-bis(2-acetoxyethyl)-2-(2-oxopropoxycarbonyl)ethylamine, N,N-bis(2-hydroxyethyl)-2-(tetrahydrofurfuryloxycarbonyl)-ethylamine, N,N-bis(2-acetoxyethyl)-2-(tetrahydrofurfuryloxycarbonyl)-ethylamine, N,N-bis(2-hydroxyethyl)-2-[(2-oxotetrahydrofuran-3-yl)oxycarbonyl]ethylamine, N,N-bis(2-acetoxyethyl)-2-[(2-oxotetrahydrofuran-3-yl)oxycarbonyl]ethylamine, N,N-bis(2-hydroxyethyl)-2-(4-hydroxybutoxycarbonyl)ethylamine, N,N-bis(2-formyloxyethyl)-2-(4-formyloxybutoxycarbonyl)-ethylamine, N,N-bis(2-formyloxyethyl)-2-(2-formyloxyethoxycarbonyl)-ethylamine, N,N-bis(2-methoxyethyl)-2-(methoxycarbonyl)ethylamine, N-(2-hydroxyethyl)-bis[2-(methoxycarbonyl)ethyl]amine, N-(2-acetoxyethyl)-bis[2-(methoxycarbonyl)ethyl]amine, N-(2-hydroxyethyl)-bis[2-(ethoxycarbonyl)ethyl]amine, N-(2-acetoxyethyl)-bis[2-(ethoxycarbonyl)ethyl]amine, N-(3-hydroxy-1-propyl)-bis[2-(methoxycarbonyl)ethyl]amine, N-(3-acetoxy-1-propyl)-bis[2-(methoxycarbonyl)ethyl]amine, N-(2-methoxyethyl)-bis[2-(methoxycarbonyl)ethyl]amine, N-butyl-bis[2-(methoxycarbonyl)ethyl]amine, N-butyl-bis[2-(2-methoxyethoxycarbonyl)ethyl]amine, N-methyl-bis(2-acetoxyethyl)amine, N-ethyl-bis(2-acetoxyethyl)amine, N-methyl-bis(2-pivaloyloxyethyl)amine, N-ethyl-bis[2-(methoxycarbonyloxy)ethyl]amine, N-ethyl-bis[2-(tert-butoxycarbonyloxy)ethyl]amine, tris(methoxycarbonylmethyl)amine, tris(ethoxycarbonylmethyl)amine, N-butyl-bis(methoxycarbonylmethyl)amine, N-hexyl-bis(methoxycarbonylmethyl)amine, and β-(diethylamino)-δ-valerolactone.

Also useful are one or more of cyclic structure-bearing amine compounds having the following general formula (B)-2.

Herein X is as defined above, and R³⁰⁷ is a straight or branched C₂-C₂₀ alkylene group in which some or all hydrogen atoms may be substituted by fluorine atoms and which may contain one or more carbonyl, ether, ester or sulfide groups.

Illustrative examples of the cyclic structure-bearing amine compounds having formula (B)-2 include 1-[2-(methoxymethoxy)ethyl]pyrrolidine, 1-[2-(methoxymethoxy)ethyl]piperidine, 4-[2-(methoxymethoxy)ethyl]morpholine, 1-[2-[(2-methoxyethoxy)methoxy]ethyl]pyrrolidine, 1-[2-[(2-methoxyethoxy)methoxy]ethyl]piperidine, 4-[2-[(2-methoxyethoxy)methoxy]ethyl]morpholine, 2-[2-(2-methoxyethoxy)ethoxy]ethylmorpholine, 2-[2-(2-butoxyethoxy)ethoxy]ethylmorpholine, 2-{2-[2-(2-methoxyethoxy)ethoxy]ethoxy}ethylmorpholine, 2-{2-[2-(2-butoxyethoxy)ethoxy]ethoxy}ethylmorpholine, 2-(1-pyrrolidinyl)ethyl acetate, 2-piperidinoethyl acetate, 2-morpholinoethyl acetate, 2-(1-pyrrolidinyl)ethyl formate, 2-piperidinoethyl propionate, 2-morpholinoethyl acetoxyacetate, 2-(1-pyrrolidinyl)ethyl methoxyacetate, 4-[2-(methoxycarbonyloxy)ethyl]morpholine, 1-[2-(t-butoxycarbonyloxy)ethyl]piperidine, 4-[2-(2-methoxyethoxycarbonyloxy)ethyl]morpholine, methyl 3-(1-pyrrolidinyl)propionate, methyl 3-piperidinopropionate, methyl 3-morpholinopropionate, methyl 3-(thiomorpholino)propionate, methyl 2-methyl-3-(1-pyrrolidinyl)propionate, ethyl 3-morpholinopropionate, methoxycarbonylmethyl 3-piperidinopropionate, 2-hydroxyethyl 3-(1-pyrrolidinyl)propionate, 2-acetoxyethyl 3-morpholinopropionate, 2-oxotetrahydrofuran-3-yl 3-(1-pyrrolidinyl)propionate, tetrahydrofurfuryl 3-morpholinopropionate, glycidyl 3-piperidinopropionate, 2-methoxyethyl 3-morpholinopropionate, 2-(2-methoxyethoxy)ethyl 3-(1-pyrrolidinyl)propionate, butyl 3-morpholinopropionate, cyclohexyl 3-piperidinopropionate, α-(1-pyrrolidinyl)methyl-γ-butyrolactone, β-piperidino-γ-butyrolactone, β-morpholino-δ-valerolactone, methyl 1-pyrrolidinylacetate, methyl piperidinoacetate, methyl morpholinoacetate, methyl thiomorpholinoacetate, ethyl 1-pyrrolidinylacetate, 2-methoxyethyl morpholinoacetate, 2-morpholinoethyl 2-methoxyacetate, 2-morpholinoethyl 2-(2-methoxyethoxy)acetate, 2-morpholinoethyl 2-[2-(2-methoxyethoxy)ethoxy]acetate, 2-morpholinoethyl hexanoate, 2-morpholinoethyl octanoate, 2-morpholinoethyl decanoate, 2-morpholinoethyl laurate, 2-morpholinoethyl myristate, 2-morpholinoethyl palmitate, 2-morpholinoethyl stearate, 2-morpholinoethyl cyclohexanecarboxylate, and 2-morpholinoethyl adamantanecarboxylate.

Also, one or more of cyano-bearing amine compounds having the following general formulae (B)-3 to (B)-6 may be added.

Herein, X, R³⁰⁷ and n are as defined in formula (B)-1, and R³⁰⁸ and R³⁰⁹ each are independently a straight or branched C₁-C₄ alkylene group.

Illustrative examples of the cyano-bearing amine compounds having formulae (B)-3 to (B)-6 include 3-(diethylamino)propiononitrile, N,N-bis(2-hydroxyethyl)-3-aminopropiononitrile, N,N-bis(2-acetoxyethyl)-3-aminopropiononitrile, N,N-bis(2-formyloxyethyl)-3-aminopropiononitrile, N,N-bis(2-methoxyethyl)-3-aminopropiononitrile, N,N-bis[2-(methoxymethoxy)ethyl]-3-aminopropiononitrile, methyl N-(2-cyanoethyl)-N-(2-methoxyethyl)-3-aminopropionate, methyl N-(2-cyanoethyl)-N-(2-hydroxyethyl)-3-aminopropionate, methyl N-(2-acetoxyethyl)-N-(2-cyanoethyl)-3-aminopropionate, N-(2-cyanoethyl)-N-ethyl-3-aminopropiononitrile, N-(2-cyanoethyl)-N-(2-hydroxyethyl)-3-aminopropiononitrile, N-(2-acetoxyethyl)-N-(2-cyanoethyl)-3-aminopropiononitrile, N-(2-cyanoethyl)-N-(2-formyloxyethyl)-3-aminopropiononitrile, N-(2-cyanoethyl)-N-(2-methoxyethyl)-3-aminopropiononitrile, N-(2-cyanoethyl)-N-[2-(methoxymethoxy)ethyl]-3-aminopropiononitrile, N-(2-cyanoethyl)-N-(3-hydroxy-1-propyl)-3-aminopropiononitrile, N-(3-acetoxy-1-propyl)-N-(2-cyanoethyl)-3-aminopropiononitrile, N-(2-cyanoethyl)-N-(3-formyloxy-1-propyl)-3-aminopropiononitrile, N-(2-cyanoethyl)-N-tetrahydrofurfuryl-3-aminopropiononitrile, N,N-bis(2-cyanoethyl)-3-aminopropiononitrile, diethylaminoacetonitrile, N,N-bis(2-hydroxyethyl)aminoacetonitrile, N,N-bis(2-acetoxyethyl)aminoacetonitrile, N,N-bis(2-formyloxyethyl)aminoacetonitrile, N,N-bis(2-methoxyethyl)aminoacetonitrile, N,N-bis[2-(methoxymethoxy)ethyl]aminoacetonitrile, methyl N-cyanomethyl-N-(2-methoxyethyl)-3-aminopropionate, methyl N-cyanomethyl-N-(2-hydroxyethyl)-3-aminopropionate, methyl N-(2-acetoxyethyl)-N-cyanomethyl-3-aminopropionate, N-cyanomethyl-N-(2-hydroxyethyl)aminoacetonitrile, N-(2-acetoxyethyl)-N-(cyanomethyl)aminoacetonitrile, N-cyanomethyl-N-(2-formyloxyethyl)aminoacetonitrile, N-cyanomethyl-N-(2-methoxyethyl)aminoacetonitrile, N-cyanomethyl-N-[2-(methoxymethoxy)ethyl)aminoacetonitrile, N-cyanomethyl-N-(3-hydroxy-1-propyl)aminoacetonitrile, N-(3-acetoxy-1-propyl)-N-(cyanomethyl)aminoacetonitrile, N-cyanomethyl-N-(3-formyloxy-1-propyl)aminoacetonitrile, N,N-bis(cyanomethyl)aminoacetonitrile, 1-pyrrolidinepropiononitrile, 1-piperidinepropiononitrile, 4-morpholinepropiononitrile, 1-pyrrolidineacetonitrile, 1-piperidineacetonitrile, 4-morpholineacetonitrile, cyanomethyl 3-diethylaminopropionate, cyanomethyl N,N-bis(2-hydroxyethyl)-3-aminopropionate, cyanomethyl N,N-bis(2-acetoxyethyl)-3-aminopropionate, cyanomethyl N,N-bis(2-formyloxyethyl)-3-aminopropionate, cyanomethyl N,N-bis(2-methoxyethyl)-3-aminopropionate, cyanomethyl N,N-bis[2-(methoxymethoxy)ethyl]-3-aminopropionate, 2-cyanoethyl 3-diethylaminopropionate, 2-cyanoethyl N,N-bis(2-hydroxyethyl)-3-aminopropionate, 2-cyanoethyl N,N-bis(2-acetoxyethyl)-3-aminopropionate, 2-cyanoethyl N,N-bis(2-formyloxyethyl)-3-aminopropionate, 2-cyanoethyl N,N-bis(2-methoxyethyl)-3-aminopropionate, 2-cyanoethyl N,N-bis[2-(methoxymethoxy)ethyl]-3-aminopropionate, cyanomethyl 1-pyrrolidinepropionate, cyanomethyl 1-piperidinepropionate, cyanomethyl 4-morpholinepropionate, 2-cyanoethyl 1-pyrrolidinepropionate, 2-cyanoethyl 1-piperidinepropionate, and 2-cyanoethyl 4-morpholinepropionate.

Also included are amine compounds having an imidazole structure and a polar functional group, represented by the general formula (B)-7.

Herein, R³¹⁰ is a straight, branched or cyclic C₂-C₂₀ alkyl group in which some or all hydrogen atoms may be substituted by fluorine atoms and which has one or more polar functional groups. The polar functional group is selected from among hydroxyl, carbonyl, ester, ether, sulfide, carbonate, cyano and acetal groups and mixtures thereof. R³¹¹, R³¹² and R³¹³ are each independently a hydrogen atom, a straight, branched or cyclic C₁-C₁₀ alkyl group, aryl group or aralkyl group.

Also included are amine compounds having a benzimidazole structure and a polar functional group, represented by the general formula (B)-8.

Herein, R³¹⁴ is a hydrogen atom, a straight, branched or cyclic C₁-C₁₀ alkyl group, aryl group or aralkyl group. R³¹⁵ is a straight, branched or cyclic C₁-C₂₀ alkyl group in which some or all hydrogen atoms may be substituted by fluorine atoms and which has one or more polar functional groups. The alkyl group contains as the polar functional group at least one group selected from among ester, acetal and cyano groups, and may additionally contain at least one group selected from among hydroxyl, carbonyl, ether, sulfide and carbonate groups.

Further included are heterocyclic nitrogen-containing compounds having a polar functional group, represented by the general formulae (B)-9 and (B)-10.

Herein, A is a nitrogen atom or ≡C—R³²². B is a nitrogen atom or ≡C—R³²³. R³¹⁶ is a straight, branched or cyclic C₂-C₂₀ alkyl group in which some or all hydrogen atoms may be substituted by fluorine atoms and which has one or more polar functional groups, the polar functional group being selected from among hydroxyl, carbonyl, ester, ether, sulfide, carbonate, cyano and acetal groups and mixtures thereof. R³¹⁷, R³¹⁸, R³¹⁹ and R³²⁰ are each independently a hydrogen atom, a straight, branched or cyclic C₁-C₁₀ alkyl group or aryl group, or a pair of R³¹⁷ and R³¹⁸ and a pair of R³¹⁹ and R³²⁰, taken together, may form a benzene, naphthalene or pyridine ring. R³²¹ is a hydrogen atom, a straight, branched or cyclic C₁-C₁₀ alkyl group or aryl group. R³²² and R³²³ each are a hydrogen atom, a straight, branched or cyclic C₁-C₁₀ alkyl group or aryl group, or a pair of R³²¹ and R³²³, taken together, may form a benzene or naphthalene ring.

Also included are organic nitrogen-containing compounds having an aromatic carboxylic acid ester structure, represented by the general formulae (B)-11 to (B)-14.

Herein R³²⁴ is a C₆-C₂₀ aryl group or C₄-C₂₀ hetero-aromatic group, in which some or all hydrogen atoms may be replaced by halogen atoms, straight, branched or cyclic C₁-C₂₀ alkyl groups, C₆-C₂₀ aryl groups, C₇-C₂₀ aralkyl groups, C₁-C₁₀ alkoxy groups, C₁-C₁₀ acyloxy groups or C₁-C₁₀ alkylthio groups. R³²⁵ is CO₂R³²⁶, OR³²⁷ or cyano group. R³²⁶ is a C₁-C₁₀ alkyl group, in which some methylene groups may be replaced by oxygen atoms. R³²⁷ is a C₁-C₁₀ alkyl or acyl group, in which some methylene groups may be replaced by oxygen atoms. R³²⁸ is a single bond, methylene, ethylene, sulfur atom or —O(CH₂CH₂O)_(n)— group wherein n is 0, 1, 2, 3 or 4. R³²⁹ is hydrogen, methyl, ethyl or phenyl. X is a nitrogen atom or CR³³⁰. Y is a nitrogen atom or CR³³¹. Z is a nitrogen atom or CR³³². R³³⁰, R³³¹ and R³³² are each independently hydrogen, methyl or phenyl. Alternatively, a pair of R³³⁰ and R³³¹ or a pair of R³³¹ and R³³² may bond together to form a C₆-C₂₀ aromatic ring or C₂-C₂₀ hetero-aromatic ring.

Further included are amine compounds of 7-oxanorbornane-2-carboxylic ester structure, represented by the general formula (B)-15.

Herein R³³³ is hydrogen or a straight, branched or cyclic C₁-C₁₀ alkyl group. R³³⁴ and R³³⁵ are each independently a C₁-C₂₀ alkyl group, C₆-C₂₀ aryl group or C₇-C₂₀ aralkyl group, which may contain one or more polar functional groups selected from among ether, carbonyl, ester, alcohol, sulfide, nitrile, amine, imine, and amide and in which some hydrogen atoms may be replaced by halogen atoms. R³³⁴ and R³³⁵, taken together, may form a heterocyclic or hetero-aromatic ring of 2 to 20 carbon atoms.

The quenchers may be used alone or in admixture of two or more. The quencher is preferably formulated in an amount of 0.001 to 2 parts, and especially 0.01 to 1 part by weight, per 100 parts by weight of the total base resin. Less than 0.001 phr of the quencher may achieve no addition effect whereas more than 2 phr may lead to too low a sensitivity.

Surfactant

Optionally, the resist composition of the invention may further comprise a surfactant which is commonly used for improving the coating characteristics. The surfactant may be added in conventional amounts so long as this does not compromise the objects of the invention.

Nonionic surfactants are preferred, examples of which include perfluoroalkylpolyoxyethylene ethanols, fluorinated alkyl esters, perfluoroalkylamine oxides, perfluoroalkyl EO-addition products, and fluorinated organosiloxane compounds. Useful surfactants are commercially available under the trade names Fluorad FC-430 and FC-431 from Sumitomo 3M, Ltd., Surflon S-141, S-145, KH-10, KH-20, KH-30 and KH-40 from Asahi Glass Co., Ltd., Unidyne DS-401, DS-403 and DS-451 from Daikin Industry Co., Ltd., Megaface F-8151 from Dai-Nippon Ink & Chemicals, Inc., and X-70-092 and X-70-093 from Shin-Etsu Chemical Co., Ltd. Preferred surfactants are Fluorad FC-430 from Sumitomo 3M, Ltd., KH-20 and KH-30 from Asahi Glass Co., Ltd., and X-70-093 from Shin-Etsu Chemical Co., Ltd. The surfactant is preferably compounded in an amount of 0.01 to 1 part, and especially 0.05 to 0.5 part by weight, per 100 parts by weight of the total base resin.

While the resist composition of the invention typically comprises a polymer or base resin, acid generator, organic solvent and quencher as described above, there may be added optional other ingredients such as dissolution inhibitors, acidic compounds, stabilizers, and dyes. Optional ingredients may be added in conventional amounts so long as this does not compromise the objects of the invention.

Pattern formation using the resist composition of the invention may be carried out by a known lithographic technique. For example, the resist composition is applied onto a substrate such as a silicon wafer by spin coating or the like to form a resist film having a thickness of 0.05 to 2.0 μm, which is then pre-baked on a hot plate at 60 to 150° C. for 1 to 10 minutes, and preferably at 80 to 140° C. for 1 to 5 minutes. A patterning mask having the desired pattern is then placed over the resist film, and the film exposed through the mask to an electron beam or to high-energy radiation such as deep-UV ray, excimer laser, or x-ray in a dose of about 1 to 200 mJ/cm², and preferably about 10 to 100 mJ/cm². Light exposure may be done by a conventional exposure process or in some cases, by an immersion process of providing liquid impregnation between the mask and the resist. The resist film is then post-exposure baked (PEB) on a hot plate at 60 to 150° C. for 1 to 5 minutes, and preferably at 80 to 140° C. for 1 to 3 minutes. Finally, development is carried out using as the developer an aqueous alkali solution, such as a 0.1 to 5 wt % (preferably 2 to 3 wt %) aqueous solution of tetramethylammonium hydroxide (TMAH), this being done by a conventional method such as dip, puddle, or spray development for a period of 0.1 to 3 minutes, and preferably 0.5 to 2 minutes. These steps result in the formation of the desired pattern on the substrate. Of the various types of high-energy radiation that may be used, the resist composition of the invention is best suited to fine pattern formation with, in particular, deep-UV rays having a wavelength of 250 to 190 nm, an excimer laser, x-rays, or an electron beam. The desired pattern may not be obtainable outside the upper and lower limits of the above range.

EXAMPLE

Examples and Comparative Examples are given below by way of illustration and not by way of limitation. The abbreviation Mw is a weight average molecular weight as measured by GPC using polystyrene standards.

Example 1

Lactone-containing compounds within the scope of the invention were synthesized according to the following formulation.

Example 1-1 Synthesis of Monomer 1

Example 1-1-1 Synthesis of 7-methoxycarbonyl-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-6-yl 2-chloroacetate

In 180 ml of tetrahydrofuran were dissolved 25.0 g of methyl 6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta-[b]furan-7-carboxylate and 16.0 g of 2-chloroacetic acid chloride. To the solution below 20° C., 10.7 g of pyridine was added dropwise. The solution was stirred at room temperature for 1 hour and combined with 40 g of a 5% aqueous solution of sodium hydrogen carbonate, followed by ordinary post-treatment. Recrystallization from isopropyl ether gave 31.5 g of the target compound (yield 93%).

¹H-NMR (600 MHz in CDCl₃): δ=1.69 (1H, dd), 2.07 (1H, d), 2.80 (1H, m), 2.84 (1H, dd), 3.11 (1H, dd), 3.35 (1H, t-like), 3.73 (3H, s), 4.06 (2H, s), 4.63 (1H, d), 5.34 (1H, s) ppm.

Example 1-1-2 Synthesis in one route of 7-methoxycarbonyl-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-6-yl 2-(methacryloyloxy)-acetate

A mixture of 28.9 g of the 2-chloroacetic ester obtained in Example 1-1-1 and 40 g of dimethylformamide was added dropwise to a mixture of 12.4 g of sodium methacrylate, 3.0 g of sodium iodide and 50 g of dimethylformamide at a temperature below 30° C. The mixture was stirred at the temperature for 8 hours. 100 ml of water was added below 30° C. This was followed by ordinary post-treatment and recrystallization from toluene and n-hexane, obtaining 29.1 g of the target compound (yield 86%).

IR (thin film): ν=3002, 2958, 1779, 1758, 1733, 1722, 1436, 1371,1340, 1220, 1205, 1199, 1155, 1052, 1006 cm⁻¹

¹H-NMR (600 MHz in CDCl₃): δ=1.67 (1H, dd), 1.96 (3H, m), 2.01 (1H, d,), 2.80 (1H, m), 2.82 (1H, dd), 3.08 (1H, dd), 3.32 (1H, t-like), 3.72 (3H, s), 4.61 (1H, d), 4.66 (2H, s), 5.33 (1H, s), 5.66 (1H, m), 6.20 (1H, s) ppm

Example 1-1-3 Synthesis in another route of 7-methoxycarbonyl-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-6-yl 2-(methacryloyloxy)acetate

A mixture of 28.9 g of the 2-chloroacetic ester obtained in Example 1-1-1 and 40 g of dimethylformamide was added dropwise to a mixture of 9.2 g of methacrylic acid, 16.2 g of potassium carbonate, 3.0 g of sodium iodide, and 50 g of dimethylformamide at a temperature below 30° C. The mixture was stirred at the temperature for 8 hours. 100 ml of water was added below 30° C. This was followed by ordinary post-treatment and recrystallization from toluene and n-hexane, obtaining 28.1 g of the target compound (yield 83%). The spectroscopic data of this compound were exactly identical with those of the compound synthesized in Example 1-1-2.

Example 1-2 Synthesis of Monomer 2

The procedure of Examples 1-1-1 and 1-1-3 was repeated aside from using acrylic acid instead of methacrylic acid. There was obtained 7-methoxycarbonyl-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-6-yl 2-(acryloyloxy)acetate. Two-step yield 80%.

Example 1-3 Synthesis of Monomer 3

The procedure of Examples 1-1-1 and 1-1-3 was repeated aside from using 2-(trifluoromethyl)acrylic acid instead of methacrylic acid. There was obtained 7-methoxycarbonyl-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-6-yl 2-[2-(trifluoromethyl)acryloyloxy]acetate. Two-step yield 74%.

Example 1-4 Synthesis of Monomer 4

The procedure of Examples 1-1-1 and 1-1-2 was repeated aside from using ethyl 6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylate instead of methyl 6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylate. There was obtained 7-ethoxycarbonyl-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-6-yl 2-(methacryloyloxy)acetate. Two-step yield 78%.

Example 1-5 Synthesis of Monomer 5 Example 1-5-1 Synthesis of 2-oxo-4-oxahexahydro-3,5-methano-2H-cyclopenta-[b]furan-6-yl 2-chloroacetate

The target compound was obtained by the same procedure as in Example 1-1-1 aside from using 6-hydroxy-2-oxo-4-oxahexahydro-3,5-methano-2H-cyclopenta[b]furan instead of methyl 6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta-[b]furan-7-carboxylate. Yield 91%.

¹H-NMR (600 MHz in DMSO-d6): δ=2.04-2.12 (2H, m), 2.68-2.73 (1H, m), 4.41 (2H, dd-like), 4.66 (1H, d), 4.70 (1H, d), 4.85 (1H, s), 5.44 (1H, t) ppm

Example 1-5-2 Synthesis of 2-oxo-4-oxahexahydro-3,5-methano-2H-cyclopenta-[b]furan-6-yl 2-(methacryloyloxy)acetate

The target compound was obtained by the same procedure as in Example 1-1-2 aside from using 2-oxo-4-oxahexahydro-3,5-methano-2H-cyclopenta[b]furan-6-yl 2-chloroacetate instead of 7-methoxycarbonyl-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-6-yl 2-chloroacetate. Yield 81%.

IR (thin film): ν=2989, 2960, 1791, 1762, 1724, 1454, 1421, 1326, 1299, 1230, 1182, 1157, 1047, 1024, 811 cm⁻¹

¹H-NMR (600 MHz in CDCl₃): δ=1.97 (3H, m), 2.07 (1H, dd), 2.25 (1H, m), 2.76 (1H, m), 4.65 (1H, d), 4.70 (2H, s), 4.72 (1H, d), 4.81 (1H, s), 5.36 (1H, t), 5.67 (1H, m), 6.21 (1H, m) ppm

Example 1-6 Synthesis of Monomer 6

The procedure of Examples 1-1-1 and 1-1-3 was repeated aside from using 6-hydroxy-2-oxo-4-oxahexahydro-3,5-methano-2H-cyclopenta[b]furan instead of methyl 6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylate and acrylic acid instead of methacrylic acid. There was obtained 2-oxo-4-oxahexahydro-3,5-methano-2H-cyclopenta[b]furan-6-yl 2-(acryloyloxy)acetate. Two-step yield 77%.

Example 1-7 Synthesis of Monomer 7

The procedure of Examples 1-1-1 and 1-1-3 was repeated aside from using 6-hydroxy-2-oxo-4-oxahexahydro-3,5-methano-2H-cyclopenta[b]furan instead of methyl 6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylate and 2-(trifluoromethyl)acrylic acid instead of methacrylic acid. There was obtained 2-oxo-4-oxahexahydro-3,5-methano-2H-cyclopenta[b]furan-6-yl 2-[2-(trifluoromethyl)acryloyloxy]-acetate. Two-step yield 73%.

Example 1-8 Synthesis of Monomer 8

The procedure of Examples 1-1-1 and 1-1-2 was repeated aside from using tert-butyl 6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylate instead of methyl 6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylate. There was obtained 7-tert-butoxycarbonyl-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-6-yl 2-(methacryloyloxy)acetate. Two-step yield 79%.

Example 1-9 Synthesis of Monomer 9

The procedure of Examples 1-1-1 and 1-1-3 was repeated aside from using tert-butyl 6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylate instead of methyl 6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylate and acrylic acid instead of methacrylic acid. There was obtained 7-tert-butoxycarbonyl-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-6-yl 2-(acryloyloxy)acetate. Two-step yield 77%.

Example 1-10 Synthesis of Monomer 10

The procedure of Examples 1-1-1 and 1-1-2 was repeated aside from using cyclohexyl 6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylate instead of methyl 6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylate. There was obtained 7-cyclohexyloxycarbonyl-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-6-yl 2-(methacryloyloxy)acetate. Two-step yield 82%.

Example 1-11 Synthesis of Monomer 11

The procedure of Examples 1-1-1 and 1-1-3 was repeated aside from using cyclohexyl 6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylate instead of methyl 6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylate and acrylic acid instead of methacrylic acid. There was obtained 7-cyclohexyloxycarbonyl-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-6-yl 2-(acryloyloxy)-acetate. Two-step yield 79%.

Example 1-12 Synthesis of Monomer 12

The procedure of Examples 1-1-1 and 1-1-3 was repeated aside from using cyclohexyl 6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylate instead of methyl 6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylate and 2-(trifluoromethyl)acrylic acid instead of methacrylic acid. There was obtained 7-cyclohexyloxycarbonyl-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-6-yl 2-[2-(trifluoromethyl)acryloyloxy]acetate. Two-step yield 73%.

Example 1-13 Synthesis of Monomer 13 Example 1-13-1 Synthesis of 7-(1-ethyl-1-cyclopentyloxycarbonyl)-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-6-yl 2-chloroacetate

The target compound was obtained by the same procedure as in Example 1-1-1 aside from using 1-ethyl-1-cyclopentyl 6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylate instead of methyl 6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylate. Yield 91%.

¹H-NMR (600 MHz in CDCl₃): δ=0.85 (3H, t), 1.56-1.71 (6H, m), 1.78 (1H, dd), 1.89-2.12 (5H, m), 2.70 (1H, s), 2.86 (1H, s), 3.09 (1H, d), 3.23 (1H, dt-like), 4.07 (2H, s), 4.56 (1H, d), 4.70 (1H, d) ppm

Example 1-13-2 Synthesis of 7-(1-ethyl-1-cyclopentyloxycarbonyl)-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-6-yl 2-(methacryloyl-oxy)acetate

The target compound was obtained by the same procedure as in Example 1-1-2 aside from using 7-(1-ethyl-1-cyclo-pentyloxycarbonyl)-2-oxohexahydro-3,5-methano-2H-cyclopenta-[b]furan-6-yl 2-chloroacetate instead of 7-methoxycarbonyl-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-yl 2-chloroacetate. Yield 76%.

IR (thin film): ν=2979, 2960, 2929, 1795, 1787, 1764, 1727, 1459, 1367, 1303, 1251, 1211, 1176, 1160, 1112, 1006 cm⁻¹

¹H-NMR (600 MHz in CDCl₃): δ=0.84 (3H, t), 1.56-1.71 (6H, m), 1.77 (1H, dd), 1.85-2.12 (8H, m), 2.68 (1H, s), 2.84 (1H, s), 3.07 (1H, d), 3.20 (1H, dt-like), 4.53 (1H, d), 4.68 (2H, s), 4.70 (1H, d), 5.68 (1H, m), 6.21 (1H, m) ppm

Example 1-14 Synthesis of Monomer 14

The procedure of Examples 1-1-1 and 1-1-3 was repeated aside from using 1-ethyl-1-cyclopentyl 6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylate instead of methyl 6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta-[b]furan-7-carboxylate and 2-(trifluoromethyl)acrylic acid instead of methacrylic acid. There was obtained 7-(1-ethyl-1-cyclopentyloxycarbonyl)-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-6-yl 2-[2-(trifluoromethyl)acryloyloxy]-acetate. Two-step yield 71%.

Example 1-15 Synthesis of Monomer 15

The procedure of Examples 1-1-1 and 1-1-2 was repeated aside from using methyl 6-hydroxy-2-oxo-4-oxahexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylate instead of methyl 6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylate. There was obtained 7-methoxycarbonyl-2-oxo-4-oxahexahydro-3,5-methano-2H-cyclopenta[b]furan-6-yl 2-(methacryloyloxy)acetate. Two-step yield 74%.

Example 1-16 Synthesis of Monomer 16

The procedure of Examples 1-1-1 and 1-1-2 was repeated aside from using 2,2,2-trifluoroethyl 6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylate instead of methyl 6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta-[b]furan-7-carboxylate. There was obtained 7-(2,2,2-trifluoroethoxycarbonyl)-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-6-yl 2-(methacryloyloxy)acetate. Two-step yield 77%.

Example 1-17 Synthesis of Monomer 17

The procedure of Examples 1-1-1 and 1-1-3 was repeated aside from using 2,2,2-trifluoroethyl 6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[(b]furan-7-carboxylate instead of methyl 6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta-[b]furan-7-carboxylate and acrylic acid instead of methacrylic acid. There was obtained 7-(2,2,2-trifluoro-ethoxycarbonyl)-2-oxohexahydro-3,5-methano-2H-cyclopenta-[b]furan-6-yl 2-(acryloyloxy)acetate. Two-step yield 72%.

Example 1-18 Synthesis of Monomer 18

The procedure of Examples 1-1-1 and 1-1-2 was repeated aside from using 2-methoxyethyl 6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylate instead of methyl 6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylate. There was obtained 7-(2-methoxyethoxycarbonyl)-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-6-yl 2-(methacryloyloxy)acetate. Two-step yield 78%.

Example 1-19 Synthesis of Monomer 19

The procedure of Examples 1-1-1 and 1-1-3 was repeated aside from using 2-methoxyethyl 6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylate instead of methyl 6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylate and acrylic acid instead of methacrylic acid. There was obtained 7-(2-methoxyethoxycarbonyl)-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-6-yl 2-(acryloyloxy)-acetate. Two-step yield 75%.

Example 2

Polymers within the scope of the invention were synthesized according to the following formulation.

Example 2-1 Synthesis of Polymer 1

In 70.0 g of methyl ethyl ketone were dissolved 22.1 g of Monomer 1, 17.9 g of 3-ethyl-3-exo-tetracyclo-[4.4.0.1^(2,5).1^(7,10) 9 dodecanyl methacrylate, and 858 mg of 2,2′-azobisisobutyronitrile. In a nitrogen atmosphere, this solution was added dropwise over 4 hours to 23.3 g of methyl ethyl ketone which was stirred at 80° C. The solution was stirred at 80° C. for a further 2 hours. The reaction solution was cooled to room temperature, and with vigorous stirring, added dropwise to 640 g of methanol. The resulting solids were collected by filtration and dried in vacuum at 50° C. for 15 hours, obtaining a white powder solid designated Polymer 1. The amount was 32.4 g in a yield of 81%. Polymer 1 had a composition and Mw shown below.

Examples 2-2 to 2-35 and Comparative Examples 1-1 to 1-3 Synthesis of Polymers 2-38

Polymers 2 to 38 were synthesized by the same procedure as Examples 2-1 except that the type and proportion of monomers were changed, with their compositional proportion (in molar ratio) and Mw being shown in Table 1. The structure of the units is shown in Tables 2 to 5.

TABLE 1 Unit 1 Unit 2 Unit 3 Unit 4 Resin (ratio) (ratio) (ratio) (ratio) Mw Example 2-1 Polymer 1 L-1M (0.50) A-1M (0.50) — — 7,100 Example 2-2 Polymer 2 L-2M (0.50) A-1M (0.50) — — 6,900 Example 2-3 Polymer 3 L-3M (0.50) A-1M (0.50) — — 7,300 Example 2-4 Polymer 4 L-4M (0.50) A-1M (0.50) — — 7,200 Example 2-5 Polymer 5 L-5M (0.50) A-1M (0.50) — — 7,400 Example 2-6 Polymer 6 L-1M (0.55) A-1M (0.30) B-1M (0.15) — 7,100 Example 2-7 Polymer 7 L-1M (0.50) A-2M (0.35) B-1M (0.15) — 7,400 Example 2-8 Polymer 8 L-1M (0.55) A-3M (0.30) B-1M (0.15) — 6,900 Example 2-9 Polymer 9 L-1M (0.55) A-4M (0.30) B-1M (0.15) — 7,300 Example 2-10 Polymer 10 L-1M (0.50) A-5M (0.35) B-1M (0.15) — 6,500 Example 2-11 Polymer 11 L-1M (0.50) A-6M (0.35) B-1M (0.15) — 7,000 Example 2-12 Polymer 12 L-2M (0.55) A-1M (0.30) B-1M (0.15) — 7,300 Example 2-13 Polymer 13 L-2M (0.50) A-2M (0.35) B-1M (0.15) — 7,500 Example 2-14 Polymer 14 L-2M (0.55) A-3M (0.30) B-1M (0.15) — 7,000 Example 2-15 Polymer 15 L-2M (0.55) A-4M (0.30) B-1M (0.15) — 7,400 Example 2-16 Polymer 16 L-2M (0.50) A-5M (0.35) B-1M (0.15) — 6,600 Example 2-17 Polymer 17 L-2M (0.50) A-6M (0.35) B-1M (0.15) — 7,100 Example 2-18 Polymer 18 L-1M (0.55) A-1M (0.30) B-2M (0.15) — 6,700 Example 2-19 Polymer 19 L-1M (0.55) A-1M (0.30) B-1A (0.15) — 6,800 Example 2-20 Polymer 20 L-1M (0.30) A-1M (0.30) B-1M (0.15) B-3M (0.25) 6,800 Example 2-21 Polymer 21 L-1M (0.30) A-1M (0.30) B-1M (0.15) B-4M (0.25) 6,700 Example 2-22 Polymer 22 L-1M (0.30) A-1M (0.30) B-1M (0.15) B-5M (0.25) 6,600 Example 2-23 Polymer 23 L-1M (0.30) A-1M (0.30) B-1M (0.15) B-6M (0.25) 6,700 Example 2-24 Polymer 24 L-1M (0.30) A-2M (0.35) B-1M (0.15) B-6M (0.20) 6,500 Example 2-25 Polymer 25 L-1M (0.30) A-3M (0.30) B-1M (0.15) B-6M (0.25) 6,900 Example 2-26 Polymer 26 L-1M (0.30) A-4M (0.30) B-1M (0.15) B-6M (0.25) 7,000 Example 2-27 Polymer 27 L-1M (0.30) A-5M (0.35) B-1M (0.15) B-6M (0.20) 7,300 Example 2-28 Polymer 28 L-1M (0.30) A-6M (0.35) B-1M (0.15) B-6M (0.20) 7,200 Example 2-29 Polymer 29 L-1M (0.45) A-1M (0.30) B-1M (0.15) C-1M (0.10) 7,000 Example 2-30 Polymer 30 L-1M (0.45) A-1M (0.30) B-1M (0.15) C-2M (0.10) 6,800 Example 2-31 Polymer 31 L-1M (0.45) A-1M (0.30) B-1M (0.15) C-3M (0.10) 6,900 Example 2-32 Polymer 32 L-1M (0.45) A-1M (0.30) B-1M (0.15) C-4M (0.10) 6,800 Example 2-33 Polymer 33 L-1M (0.45) A-1M (0.30) B-1M (0.15) C-5M (0.10) 6,700 Example 2-34 Polymer 34 L-2M (0.30) A-1M (0.30) B-1M (0.15) B-6M (0.25) 6,800 Example 2-35 Polymer 35 L-2M (0.30) A-3M (0.30) B-1M (0.15) B-6M (0.25) 7,300 Comparative Polymer 36 — A-3M (0.30) B-1M (0.15) B-4M (0.55) 6,900 Example 1-1 Comparative Polymer 37 — A-3M (0.30) B-1M (0.15) B-6M (0.55) 6,600 Example 1-2 Comparative Polymer 38 — A-3M (0.30) B-1M (0.15) B-7M (0.55) 7,200 Example 1-3

TABLE 2 L-1M (R = CH₃) L-2M (R = CH₃) L-1A (R = H) L-2A (R = H)

L-3M (R = CH₃) L-4M (R = CH₃) L-3A (R = H) L-4A (R = H)

L-5M (R = CH₃) L-5A (R = H)

TABLE 3 A-1M (R = CH₃) A-2M (R = CH₃) A-1A (R = H) A-2A (R = H)

A-3M (R = CH₃) A-4M (R = CH₃) A-3A (R = H) A-4A (R = H)

A-5M (R = CH₃) A-6M (R = CH₃) A-5A (R = H) A-6A (R = H)

TABLE 4 B-1M (R = CH₃) B-2M (R = CH₃) B-1A (R = H) B-2A (R = H)

B-3M (R = CH₃) B-4M (R = CH₃) B-3A (R = H) B-4A (R = H)

B-5M (R = CH₃) B-6M (R = CH₃) B-5A (R = H) B-6A (R = H)

B-7M (R = CH₃) B-7A (R = H)

TABLE 5 C-1M (R = CH₃) C-2M (R = CH₃) C-1A (R = H) C-2A (R = H)

C-3M (R = CH₃) C-4M (R = CH₃) C-3A (R = H) C-4A (R = H)

C-5M (R = CH₃) C-5A (R = H)

Preparation of Resist Compositions Examples 3-1 to 3-59 & Comparative Examples 2-1 to 2-3

Resist compositions were prepared by using inventive resins (Polymer 1 to 35, abbreviated P01 to P35) or comparative resins (Polymers 36 to 38, abbreviated P36 to P38) as the base resin, and dissolving the polymer, an acid generator (PAG), and a quencher (Base) in a solvent mixture (PGMEA and CyHO) containing 0.01 wt % of surfactant KH-20 (Asahi Glass Co., Ltd.) in accordance with the recipe shown in Table 6. These compositions were each filtered through a Teflon® filter having a pore diameter 0.2 μm, thereby giving inventive resist solutions (R-01 to 59) and comparative resist solutions (R-60 to 62).

TABLE 6 Resin PAG Base Solvent 1 Solvent 2 Resist (pbw) (pbw) (pbw) (pbw) (pbw) Example 3-1 R-01 Polymer 01 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-2 R-02 Polymer 02 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-3 R-03 Polymer 03 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-4 R-04 Polymer 04 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-5 R-05 Polymer 05 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-6 R-06 Polymer 06 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-7 R-07 Polymer 07 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-8 R-08 Polymer 08 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-9 R-09 Polymer 09 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-10 R-10 Polymer 10 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-11 R-11 Polymer 11 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-12 R-12 Polymer 12 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-13 R-13 Polymer 13 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-14 R-14 Polymer 14 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-15 R-15 Polymer 15 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-16 R-16 Polymer 16 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-17 R-17 Polymer 17 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-18 R-18 Polymer 18 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-19 R-19 Polymer 19 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-20 R-20 Polymer 20 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-21 R-21 Polymer 21 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-22 R-22 Polymer 22 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-23 R-23 Polymer 23 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-24 R-24 Polymer 24 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-25 R-25 Polymer 25 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-26 R-26 Polymer 26 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-27 R-27 Polymer 27 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-28 R-28 Polymer 28 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-29 R-29 Polymer 29 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-30 R-30 Polymer 30 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-31 R-31 Polymer 31 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-32 R-32 Polymer 32 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-33 R-33 Polymer 33 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-34 R-34 Polymer 34 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-35 R-35 Polymer 35 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-36 R-36 Polymer 06 (80) PAG-2 (4.9) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-37 R-37 Polymer 12 (80) PAG-2 (4.9) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-38 R-38 Polymer 23 (80) PAG-2 (4.9) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-39 R-39 Polymer 25 (80) PAG-2 (4.9) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-40 R-40 Polymer 34 (80) PAG-2 (4.9) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-41 R-41 Polymer 35 (80) PAG-2 (4.9) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-42 R-42 Polymer 06 (80) PAG-3 (4.7) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-43 R-43 Polymer 12 (80) PAG-3 (4.7) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-44 R-44 Polymer 23 (80) PAG-3 (4.7) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-45 R-45 Polymer 25 (80) PAG-3 (4.7) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-46 R-46 Polymer 34 (80) PAG-3 (4.7) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-47 R-47 Polymer 35 (80) PAG-3 (4.7) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-48 R-48 Polymer 06 (80) PAG-1 (2.2) Base-1 (0.94) PGMEA (560) CyHO (240) PAG-3 (2.3) Example 3-49 R-49 Polymer 12 (80) PAG-1 (2.2) Base-1 (0.94) PGMEA (560) CyHO (240) PAG-3 (2.3) Example 3-50 R-50 Polymer 23 (80) PAG-1 (2.2) Base-1 (0.94) PGMEA (560) CyHO (240) PAG-3 (2.3) Example 3-51 R-51 Polymer 25 (80) PAG-1 (2.2) Base-1 (0.94) PGMEA (560) CyHO (240) PAG-3 (2.3) Example 3-52 R-52 Polymer 34 (80) PAG-1 (2.2) Base-1 (0.94) PGMEA (560) CyHO (240) PAG-3 (2.3) Example 3-53 R-53 Polymer 35 (80) PAG-1 (2.2) Base-1 (0.94) PGMEA (560) CyHO (240) PAG-3 (2.3) Example 3-54 R-54 Polymer 06 (80) PAG-1 (4.4) Base-2 (0.74) PGMEA (560) CyHO (240) Example 3-55 R-55 Polymer 12 (80) PAG-1 (4.4) Base-2 (0.74) PGMEA (560) CyHO (240) Example 3-56 R-56 Polymer 23 (80) PAG-1 (4.4) Base-2 (0.74) PGMEA (560) CyHO (240) Example 3-57 R-57 Polymer 25 (80) PAG-1 (4.4) Base-2 (0.74) PGMEA (560) CyHO (240) Example 3-58 R-58 Polymer 34 (80) PAG-1 (4.4) Base-2 (0.74) PGMEA (560) CyHO (240) Example 3-59 R-59 Polymer 35 (80) PAG-1 (4.4) Base-2 (0.74) PGMEA (560) CyHO (240) Comparative Example 2-1 R-60 Polymer 36 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Comparative Example 2-2 R-61 Polymer 37 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Comparative Example 2-3 R-62 Polymer 38 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240)

The acid generator, quencher (base) and solvent shown in Table 6 have the following meanings.

-   PAG-1: triphenylsulfonium nonafluorobutanesulfonate -   PAG-2: 4-t-butoxyphenyldiphenylsulfonium nonafluorobutanesulfonate -   PAG-3: triphenylsulfonium     1,1,3,3,3-pentafluoro-2-cyclohexylcarboxypropanesulfonate -   Base-1: tri(2-methoxymethoxyethyl)amine -   Base-2: 2-(2-methoxyethoxymethoxy)ethylmorpholine -   PGMEA: 1-methoxyisopropyl acetate -   CyHO: cyclohexanone

Evaluation of Resolution and Line Edge Roughness Examples 4-1 to 4-59 & Comparative Examples 3-1 to 3-4

Each of inventive resist compositions (R-01 to 59) and comparative resist compositions (R-60 to 62) was spin coated on a silicon wafer having an antireflective coating (ARC-29A, Nissan Chemical Co., Ltd.) of 78 nm thick and baked at 110° C. for 60 seconds, forming a resist film of 170 nm thick. The wafer was exposed by means of an ArF excimer laser stepper (Nikon Corp., NA 0.85), post-exposure baked (PEB) for 60 seconds, and puddle developed with a 2.38 wt % tetramethylammonium hydroxide aqueous solution for 30 seconds, forming a 1:1 line-and-space pattern and a 1:10 isolated line pattern. During the PEB, an optimum temperature for each resist composition was employed.

The patterned wafer was observed under a top-down scanning electron microscope (TDSEM). The optimum exposure (Eop) was defined as the exposure dose (mJ/cm²) which provided a 1:1 resolution at the top and bottom of a 90-nm 1:1 line-and-space pattern. The maximum resolution of the resist was defined as the minimum line width (on-mask size, in increments of 5 nm) of a 1:1 line-and-space pattern that was resolved and separated at the optimum exposure, with smaller values indicating better resolution. The 1:10 isolated line pattern at the optimum exposure was also observed for determining an actual on-wafer size of the isolated line pattern with an on-mask size of 140 nm, which was reported as mask fidelity (on-wafer size, a larger size being better). Further, a line portion of the 90-nm 1:1 line-and-space pattern was examined for line edge roughness (LER). For each of left and right edges of a line, measurement was made at 16 points along a measurement region of 300 nm long. Provided that L and R represent averages of fluctuations of measurement points from the center line along the left and right edges, respectively, a square root of (L²+R²) is reported as LER (in nm, smaller fluctuation being better).

Table 7 tabulates the test results (maximum resolution, mask fidelity and LER) of the inventive and comparative resist compositions.

TABLE 7 Maximum Mask Resist PEB temp. Eop resolution fidelity LER Example 4-1 R-01  95° C. 41.0 mJ/cm² 75 nm 85 nm 5.4 nm Example 4-2 R-02  95° C. 43.0 mJ/cm² 75 nm 88 nm 5.7 nm Example 4-3 R-03  95° C. 39.0 mJ/cm² 75 nm 84 nm 5.3 nm Example 4-4 R-04  95° C. 38.0 mJ/cm² 75 nm 83 nm 5.1 nm Example 4-5 R-05  95° C. 36.0 mJ/cm² 80 nm 83 nm 5.1 nm Example 4-6 R-06 105° C. 40.0 mJ/cm² 70 nm 84 nm 5.0 nm Example 4-7 R-07 120° C. 42.0 mJ/cm² 75 nm 85 nm 5.5 nm Example 4-8 R-08 105° C. 42.0 mJ/cm² 70 nm 85 nm 5.2 nm Example 4-9 R-09 120° C. 41.0 mJ/cm² 75 nm 83 nm 5.4 nm Example 4-10 R-10 105° C. 43.0 mJ/cm² 70 nm 80 nm 5.0 nm Example 4-11 R-11 105° C. 43.0 mJ/cm² 70 nm 86 nm 4.9 nm Example 4-12 R-12 105° C. 42.0 mJ/cm² 70 nm 87 nm 5.2 nm Example 4-13 R-13 120° C. 45.0 mJ/cm² 70 nm 87 nm 5.6 nm Example 4-14 R-14 105° C. 44.0 mJ/cm² 70 nm 89 nm 5.4 nm Example 4-15 R-15 120° C. 43.0 mJ/cm² 70 nm 86 nm 5.5 nm Example 4-16 R-16 105° C. 45.0 mJ/cm² 70 nm 84 nm 5.2 nm Example 4-17 R-17 105° C. 45.0 mJ/cm² 70 nm 90 nm 5.0 nm Example 4-18 R-18 105° C. 41.0 mJ/cm² 70 nm 86 nm 5.2 nm Example 4-19 R-19 100° C. 42.0 mJ/cm² 75 nm 80 nm 5.1 nm Example 4-20 R-20 105° C. 44.0 mJ/cm² 70 nm 92 nm 5.2 nm Example 4-21 R-21 105° C. 41.0 mJ/cm² 70 nm 89 nm 5.2 nm Example 4-22 R-22 105° C. 42.0 mJ/cm² 70 nm 90 nm 5.0 nm Example 4-23 R-23 105° C. 40.0 mJ/cm² 70 nm 86 nm 4.8 nm Example 4-24 R-24 120° C. 41.0 mJ/cm² 70 nm 87 nm 5.4 nm Example 4-25 R-25 105° C. 43.0 mJ/cm² 70 nm 89 nm 5.1 nm Example 4-26 R-26 120° C. 42.0 mJ/cm² 70 nm 85 nm 5.2 nm Example 4-27 R-27 105° C. 43.0 mJ/cm² 70 nm 84 nm 4.8 nm Example 4-28 R-28 105° C. 43.0 mJ/cm² 70 nm 89 nm 4.7 nm Example 4-29 R-29 105° C. 45.0 mJ/cm² 70 nm 86 nm 5.3 nm Example 4-30 R-30 105° C. 40.0 mJ/cm² 70 nm 84 nm 5.1 nm Example 4-31 R-31 105° C. 41.0 mJ/cm² 70 nm 85 nm 5.2 nm Example 4-32 R-32 105° C. 40.0 mJ/cm² 70 nm 84 nm 5.0 nm Example 4-33 R-33 105° C. 41.0 mJ/cm² 70 nm 85 nm 5.0 nm Example 4-34 R-34 105° C. 43.0 mJ/cm² 70 nm 89 nm 5.0 nm Example 4-35 R-35 105° C. 46.0 mJ/cm² 70 nm 92 nm 5.2 nm Example 4-36 R-36 105° C. 45.0 mJ/cm² 70 nm 86 nm 5.1 nm Example 4-37 R-37 105° C. 46.0 mJ/cm² 70 nm 88 nm 5.2 nm Example 4-38 R-38 105° C. 44.0 mJ/cm² 70 nm 88 nm 4.9 nm Example 4-39 R-39 105° C. 47.0 mJ/cm² 70 nm 92 nm 5.2 nm Example 4-40 R-40 105° C. 47.0 mJ/cm² 70 nm 92 nm 5.1 nm Example 4-41 R-41 105° C. 50.0 mJ/cm² 70 nm 94 nm 5.2 nm Example 4-42 R-42 105° C. 42.0 mJ/cm² 70 nm 88 nm 5.0 nm Example 4-43 R-43 105° C. 44.0 mJ/cm² 70 nm 90 nm 5.1 nm Example 4-44 R-44 105° C. 41.0 mJ/cm² 70 nm 90 nm 4.8 nm Example 4-45 R-45 105° C. 45.0 mJ/cm² 70 nm 92 nm 5.0 nm Example 4-46 R-46 105° C. 45.0 mJ/cm² 70 nm 93 nm 5.0 nm Example 4-47 R-47 105° C. 48.0 mJ/cm² 70 nm 96 nm 5.1 nm Example 4-48 R-48 105° C. 41.0 mJ/cm² 70 nm 86 nm 5.0 nm Example 4-49 R-49 105° C. 42.0 mJ/cm² 70 nm 89 nm 5.2 nm Example 4-50 R-50 105° C. 40.0 mJ/cm² 70 nm 88 nm 4.9 nm Example 4-51 R-51 105° C. 44.0 mJ/cm² 70 nm 91 nm 5.2 nm Example 4-52 R-52 105° C. 43.0 mJ/cm² 70 nm 92 nm 5.1 nm Example 4-53 R-53 105° C. 47.0 mJ/cm² 70 nm 94 nm 5.2 nm Example 4-54 R-54 105° C. 40.0 mJ/cm² 70 nm 85 nm 4.8 nm Example 4-55 R-55 105° C. 41.0 mJ/cm² 70 nm 88 nm 5.0 nm Example 4-56 R-56 105° C. 39.0 mJ/cm² 70 nm 88 nm 4.6 nm Example 4-57 R-57 105° C. 42.0 mJ/cm² 70 nm 90 nm 4.8 nm Example 4-58 R-58 105° C. 42.0 mJ/cm² 70 nm 90 nm 4.8 nm Example 4-59 R-59 105° C. 44.0 mJ/cm² 70 nm 93 nm 5.0 nm Comparative Example 3-1 R-60 110° C. 38.0 mJ/cm² 80 nm 78 nm 7.8 nm Comparative Example 3-2 R-60 105° C. 45.0 mJ/cm² 70 nm 88 nm 8.8 nm Comparative Example 3-3 R-61 105° C. 38.0 mJ/cm² 75 nm 84 nm 7.1 nm Comparative Example 3-4 R-62 105° C. 37.0 mJ/cm² 80 nm 76 nm 5.5 nm

It is seen from the results of Table 7 that the resist compositions within the scope of the invention have improved resolution and minimized LER when processed by ArF excimer laser lithography. The data of Comparative Examples in Table 7 reveal that prior art resist compositions satisfy either one or none of resolution and LER. It has been demonstrated that resist compositions comprising polymers comprising recurring units derived from the lactone-containing compounds of the invention are improved in resist properties over the prior art resist compositions.

Japanese Patent Application No. 2006-206233 is incorporated herein by reference.

Although some preferred embodiments have been described, many modifications and variations may be made thereto in light of the above teachings. It is therefore to be understood that the invention may be practiced otherwise than as specifically described without departing from the scope of the appended claims. 

1. A lactone-containing compound having the general formula (1):

wherein R¹ is hydrogen, fluorine, methyl or trifluoromethyl, R² and R³ are each independently a straight, branched or cyclic monovalent hydrocarbon group of 1 to 10 carbon atoms, or R² and R³ may bond together to form an aliphatic hydrocarbon ring with the carbon atom to which they are attached, R⁴ is hydrogen or CO₂R⁵, R⁵ is a straight, branched or cyclic monovalent hydrocarbon group of 1 to 15 carbon atoms which may have a halogen or oxygen atom, W is CH₂, O or S, with the proviso that R⁴ is CO₂R⁵ when W is CH₂, and R⁴ is hydrogen or CO₂R⁵ when W is O or S, and k¹ is 0 or
 1. 2. A polymer comprising recurring units derived from the lactone-containing compound of claim
 1. 3. A polymer comprising recurring units having the general formula (2):

wherein R¹ is hydrogen, fluorine, methyl or trifluoromethyl, R² and R³ are each independently a straight, branched or cyclic monovalent hydrocarbon group of 1 to 10 carbon atoms, or R² and R³ may bond together to form an aliphatic hydrocarbon ring with the carbon atom to which they are attached, R⁴ is hydrogen or CO₂R⁵, R⁵ is a straight, branched or cyclic monovalent hydrocarbon group of 1 to 15 carbon atoms which may have a halogen or oxygen atom, W is CH₂, O or S, with the proviso that R⁴ is CO₂R⁵ when W is CH₂, and R⁴ is hydrogen or CO₂R⁵ when W is O or S, and k¹ is 0 or
 1. 4. The polymer of claim 2, further comprising recurring units having at least one of the general formulas (3) to (6):

wherein R¹ is as defined above, R⁶ and R⁷ are each independently hydrogen or hydroxyl, X is an acid labile group, Y is a substituent group having a lactone structure different from formula (1), and Z is hydrogen, a fluoroalkyl group of 1 to 15 carbon atoms or a fluoroalcohol-containing substituent group of 1 to 15 carbon atoms.
 5. A resist composition comprising the polymer of claim 2 as a base resin.
 6. A process for forming a pattern comprising the steps of applying the resist composition of claim 5 onto a substrate to form a coating, heat treating the coating, exposing the coating to high-energy radiation or electron beam through a photomask, optionally heat treating the exposed coating, and developing it with a developer. 